Process for producing olefins

ABSTRACT

A process is described for producing olefins from a vapor product stream from an oxygenate to olefin conversion reaction, the vapor product stream comprising C 2  to C 4  olefins, C 5 + hydrocarbons, at least one oxygenate and water. In the process, the vapor product stream is cooled to remove water therefrom and produce a first vapor effluent stream. The first vapor effluent stream is then cooled and compressed to produce a condensed liquid effluent stream comprising C 5 + hydrocarbons and at least one oxygenate, and a residual vapor effluent stream comprising C 2  to C 4  olefins. At least part of the condensed liquid effluent stream is contacted with a liquid water-containing stream in a liquid-liquid contacting device to at least partly separate said condensed liquid effluent stream, or portion thereof, into an aqueous phase rich in said at least one oxygenate and an organic phase rich in said C 5 + hydrocarbons.

FIELD

The present invention relates to a process for producing olefins and, inparticular, ethylene and/or propylene.

BACKGROUND

Olefins are traditionally produced from petroleum feedstocks bycatalytic or steam cracking processes. These cracking processes,especially steam cracking, produce light olefin(s), such as ethyleneand/or propylene, from a variety of hydrocarbon feedstocks. Ethylene andpropylene are important commodity petrochemicals useful in a variety ofprocesses for making plastics and other chemical compounds.

The petrochemical industry has known for some time that oxygenates,especially alcohols, are convertible into light olefin(s). There arenumerous technologies available for producing oxygenates includingfermentation or reaction of synthesis gas derived from natural gas,petroleum liquids or carbonaceous materials including coal, recycledplastics, municipal waste or any other organic material. Generally, theproduction of synthesis gas involves a combustion reaction of naturalgas, mostly methane, and an oxygen source into hydrogen, carbon monoxideand/or carbon dioxide. Other known syngas production processes includeconventional steam reforming, autothermal reforming, or a combinationthereof.

The preferred process for converting an oxygenate, such as methanol,into one or more olefin(s), primarily ethylene and/or propylene,involves contacting the feedstock with a catalyst composition, typicallycontaining a molecular sieve catalyst. The product stream from such aprocess is a complex mixture comprising the desired light olefins,unconverted oxygenates, by-product oxygenates, heavier hydrocarbons andlarge amounts of water. The separation and purification of this mixtureto recover the light olefins and other valuable by-products is criticalto the overall efficiency and cost effectiveness of the process. Inparticular, it is important that the purification scheme producesproducts that are substantially free of impurities, which couldadversely effect downstream processing.

For example, certain oxygenate components present in the product from anoxygenate to olefin conversion (OTO) process, particularly aldehydes andketones, may cause problems in olefin recovery operations and inderivative manufacturing processes that feed and react C₄+ hydrocarbons.Various schemes have therefore been proposed for removing aldehydes andketones from the olefinic and C₄+ hydrocarbon components of oxygenateconversion effluent streams.

U.S. Pat. No. 6,303,841 and U.S. patent application Publication No.2002/0007101, published Jan. 17, 2002, disclose a process for producingethylene from oxygenates in which the oxygenate conversion effluentstream is compressed in a multi-stage compressor to a pressure of 1050to 2860 kPa (150 to 400 psia), preferably 1750 to 2450 kPa (250 to 350psia), washed with methanol and then water to remove unreactedoxygenates and then contacted with caustic to remove carbon dioxide. Thecarbon dioxide depleted stream is dried with a solid desiccant andpassed to a deethanizer zone to provide a light hydrocarbon feedstreamcomprising hydrogen, methane, ethylene and ethane, and a deethanizedstream comprising propylene, propane, and C₄+ olefins. The lighthydrocarbon stream is passed to a demethanizer zone operating at atemperature greater than −45° C. to provide a bottom stream comprisingethylene and ethane and an overhead stream comprising hydrogen, methane,and ethylene. The bottom stream is fed to a C₂ splitter zone to producethe ethylene product stream and an ethane stream, whereas the overheadstream is fed to a pressure swing adsorption zone to remove hydrogen andmethane and produce an ethylene-containing stream which is combined withthe oxygenate conversion effluent stream.

U.S. Pat. Nos. 6,403,854 and 6,459,009 to Miller et al. disclose aprocess for converting oxygenate to light olefins in which the reactoreffluent is quenched with an aqueous stream in a two-stage process tofacilitate the separation of hydrocarbon gases from any entrainedcatalyst fines, as well as to remove water and any heavy by-productssuch as C₆+ hydrocarbons. A portion of the waste water stream withdrawnfrom the bottom of the quench tower is recycled to the quench tower at apoint above where the reactor effluent is introduced to the quenchtower. The vapor product stream from the quench tower is compressed,passed to an adsorption zone for the selective removal of oxygenates andthen passed to a caustic wash zone for removal of carbon dioxide. Theresultant carbon dioxide free light olefin stream is passed to a dryerzone for the removal of water and passed to a conventional light olefinrecovery zone.

U.S. patent application Publication No. 2003/0130555, published Jul. 10,2003, discloses a process for separating oxygenated hydrocarbons fromthe olefin product of an oxygenate to conversion olefins reaction. Theproduct is initially sent to a cooling unit, such as a quench tower,from which cooled olefin product is separated as an olefin vapor stream.The water containing bottoms stream can be recycled through a heatexchanger for cooling and/or removed from the cooling unit to a firstseparator, such as a distillation column, to provide an oxygenatedhydrocarbon product of reduced water content and remaining water as abottoms product. The olefin vapor stream is compressed to at least 30psia (207 kPa), preferably 100 to 500 psia (689 to 3447 kPa), anddirected to a second separator that provides an olefin vapor product anda liquid oxygenated hydrocarbon-containing stream. The liquid oxygenatedhydrocarbon containing stream can then be combined with the watercontaining bottoms stream or directly added to the first separator toprovide an oxygenated hydrocarbon product recovered from the firstseparator that is reduced in water content and can be used as fuel orco-feed for the oxygenate reaction process. Before or after thecompression step, the olefin vapor can be washed with methanol and/orwater at a temperature of 40 to 200° F. (4 to 93° C.), preferably 80 to120° F. (27 to 49° C.).

In addition, U.S. patent application Ser. No. 10/871394, filed Jun. 18,2004, discloses a process for producing olefins from the vaporous firsteffluent stream from an oxygenate to olefin conversion reaction, saidvaporous first effluent stream comprising C₂ and C₃ olefins, C₄hydrocarbons, and C₂ to C₆ carbonyl compounds. In the process, thetemperature and pressure of the vaporous first effluent stream areadjusted to produce a second effluent stream having a pressure rangingfrom about 100 psig to about 350 psig (790 to 2514 kPa) and atemperature ranging from about 70° F. to about 120° F. (21 to 49° C.),wherein the second effluent stream contains about 50 wt. % or more C₄hydrocarbons based upon the total weight of C₄ hydrocarbons in the firsteffluent stream. The second effluent stream is then washed with analcohol to remove carbonyl compounds and produce a third effluentstream, whereafter the third effluent stream is washed with water toprovide a fourth effluent stream comprising the C₂ and C₃ olefins andabout 1.0 wt. % or less of the C₂ to C₆ carbonyl compounds.

All of the above references are incorporated herein by reference intheir entirety.

The unconverted and by-product oxygenates removed from theolefin-containing product streams in the above processes are valuablematerials and are generally recycled backed to the OTO reactor forconversion to olefins. However, these oxygenate-containing streams alsotypically contain heavy (C₅+) hydrocarbons, including aromaticcompounds, that are considerably less reactive than the other componentsin the OTO feed and so, if not removed, can build up to unacceptablelevels in the the reaction/purification system. Moreover, separation ofheavy hydrocarbons from oxygenates, such as methanol, is difficult byconventional fractionation. For example, the normal boiling point ofmethanol is 140° F. (60° C.), whereas those of hexane and benzene are156° F. (69° C.) and 176° F. (80° C.) respectively, and conventionalfractional distillation would need to employ an expensive column havingmany trays with high reboiler and condenser duties to make anyappreciable separation There is therefore a need for an improved methodfor separating heavy hydrocarbons from OTO effluent streams.

SUMMARY

In one aspect, the invention relates to a process for producing olefinscomprising:

(a) providing a vapor product stream from an oxygenate to olefinconversion reaction comprising C₂ to C₄ olefins, C₅+ hydrocarbons, atleast one oxygenate and water;

(b) cooling the vapor product stream to remove water therefrom andproduce a first vapor effluent stream;

(c) compressing and cooling the first vapor effluent stream to produce acondensed liquid effluent stream comprising C₅+ hydrocarbons and atleast one oxygenate and a residual vapor effluent stream comprising C₂to C₄ olefins; and

(d) contacting at least a portion of the condensed liquid effluentstream with a liquid water-containing stream in a liquid-liquidcontacting device to at least partly separate said condensed liquideffluent stream, or portion thereof, into an aqueous phase rich in saidat least one oxygenate and an organic phase rich in said C₅+hydrocarbons.

In one embodiment, the vapor product stream in (a) comprises C₂ to C₆carbonyls. Conveniently, the first vapor effluent stream comprises fromabout 0.5 to about 5 wt %, such as from about 1 to about 4 wt %, of saidcarbonyl compounds. In other alternatives, there is no more than 5 wt.%, such as no more than 2 wt. % water in the first vapor effluentstream, while in others there is at least 0.1 wt. % and no greater than5 wt/% water.

Conveniently, said at least one oxygenate includes an alcohol, forexample methanol, or ethanol, or mixtures thereof. Typically, said vaporproduct stream in (a) comprises from about 0.1 wt. % to about 20 wt. %methanol, say from about 1 wt. % to about 10 wt. % methanol.

Conveniently, the first vapor effluent stream produced in (b) has apressure ranging from about 108 kPaa (1 psig) to about 1480 kpaa (200psig), such as from about 108 kPaa (1 psig) to about 791 kPaa (100psia), for example from about 136 kPaa (5 psig) to about 377 kPaa (40psig). Typically, the first vapor effluent stream produced in (b) has atemperature ranging from about 20° C. (68° F.) to about 54° C. (130°F.), such as from about 32° C. (90° F.) to about 43° C. (110° F.).

Conveniently, the residual vapor effluent stream and condensed liquideffluent stream produced in (c) each have a pressure ranging from about446 kPaa (50 psig) to about 2514 kPaa (350 psig), such as from about 791kPaa (100 psig) to about 2100 kPaa (290 psig), for example from about1066 kPaa (140 psig) to about 1342 kPaa (180 psig). Generally, theresidual vapor effluent stream and condensed liquid effluent streamproduced in (c) are at a temperature ranging from about 20° C. (68° F.)to about 54° C. (130° F.), such as from about 32° C. (90° F.) to about43° C. (110° F.).

In one embodiment, (c) comprises compressing the first vapor effluentstream, cooling the compressed first vapor effluent stream to form acondensate, and providing the condensate to a vessel to separate thecondensed liquid effluent stream and the residual vapor effluent stream.Conveniently, the condensed liquid effluent stream produced in (c) isexposed to one or more reductions in pressure to form a flash liquideffluent stream and a flash vapor effluent stream, and the flash liquideffluent stream is provided as the condensed liquid effluent stream forcontacting (d). In a modification, at least a portion of the flash vaporeffluent stream is provided along with the first vapor effluent streamfor compression and cooling (c). The pressure of the flash liquideffluent stream will be lower than the condensed liquid effluent streamfrom which it is derived, and conveniently ranges from about 108 kPaa (1psig) to about 2169 kPaa (300 psig), such as from about 170 kPaa (10psig) to about 1480 kPaa (200 psig).

In another embodiment, (c) comprises compressing the first vaporeffluent stream, cooling the compressed first vapor effluent stream toproduce a first condensed liquid effluent stream and a first residualvapor effluent stream, compressing the first residual vapor effluentstream and cooling the compressed first residual vapor effluent streamto produce a second residual vapor effluent stream and a secondcondensed liquid effluent stream. Thus, the liquid effluent streamproduced in (c) and provided for contacting (d) can comprise the firstcondensed liquid effluent stream, the second condensed liquid effluentstream, portions thereof, or mixtures thereof. Conveniently, the secondcondensed liquid effluent stream is exposed to one or more reductions inpressure to form a flash liquid effluent stream and a flash vaporeffluent stream, and the flash liquid effluent stream is provided as thecondensed liquid effluent stream for contacting (d). In a modificationat least a portion of the flash vapor effluent stream is provided alongwith the first residual vapor effluent stream for compression andcooling.

Conveniently, the condensed liquid effluent stream produced in (c)comprises up to about 90 wt. % C₅+ hydrocarbon, or up to about 70 wt. %C₅+ hydrocarbon, or up to about 50 C₅+ hydrocarbon, or up to about 30wt. % C₅+ hydrocarbon. In another aspect, the condensed liquid effluentstream comprises at least about 1 wt. % C₅+ hydrocarbon, such as atleast about 5 wt. % C₅+ hydrocarbon, for example at least about about 10wt. % C₅+ hydrocarbon, more particularly at least about 20 wt. % C₅+hydrocarbon. Advantageously, the condensed liquid effluent streamcomprises no more than about 40 wt. % aromatics, such as no more thanabout 30 wt. % aromatics, more specifically no more than about 20 wt. %aromatics, for example no more than about 10 wt. % aromatics, includingno more than about 5 wt. % aromatics, and generally at least about 0.1wt. % aromatics, for example at least about 1 wt. % aromatics, such as aleast about 2 wt. % aromatics, more particularly at least about 4 wt. %aromatics.

In another embodiment, the condensed liquid effluent stream produced in(c) comprises no more than about 10 wt. % benzene, such as no more thanabout 5 wt. % benzene, for example no more than about 1 wt. % benzene,including no more than about 0.5 wt. % benzene, more specifically nomore than about 0.1 wt. % benzene. Conveniently, the condensed liquideffluent stream comprises no more than about 50 wt. % C₅+ saturates,such as no more than about 30 wt. % C₅+ saturates, including no morethan about 10 wt. % C₅+ saturates, for example no more than about 5 wt.% C₅+ saturates, and typically at least about 0.1 wt. % C₅+ saturates,for example at least about 1 wt. % C₅+ saturates, such as a least about2 wt. % C₅+ saturates, more particularly at least about 4 wt. % C₅+saturates. Conveniently, the condensed liquid effluent stream comprisesat least about 1 wt. % oxygenate, such as at least about 5 wt. %oxygenate, for example at least about 10 wt. % oxygenate, morespecifically at least about 20 wt. % oxygenate, including at least about30 wt. % oxygenate.

In another embodiment, the at least one oxygenate in the vapor productstream is one or more C₂ to C₆ carbonyl species, for example, ethanal,or acetone, or mixtures thereof. Conveniently, the condensed liquideffluent stream produced in (c) comprises at least about 0.1 wt. % C₂ toC₆ carbonyls, or at least about 1 wt. % C₂ to C₆ carbonyls, or at leastabout 2 wt. % C₂ to C₆ carbonyls, or at least about 5 wt. % C₂ to C₆carbonyls, or at least about 10 wt. % C₂ to C₆ carbonyls.

Conveniently, the contacting (d) comprises feeding the water-containingwash liquid to the liquid-liquid contacting device at a first rate andfeeding the condensed stream to the liquid-liquid contacting device at asecond rate. The weight ratio of the second rate to the first rateranges from about 0.1 to about 10, such as from about 0.2 to about 2,for example about 0.3 to about 1.4, such as about 0.6 to about 1.2.Where, said at least one oxygenated hydrocarbon includes methanol, theweight ratio of methanol in the second rate to the first rate rangesfrom about 0.1 to about 1, such as from about 0.2 to about 0.7, forexample from about 0.3 to about 0.6.

Conveniently, the liquid water-containing stream comprises at leastabout 80 wt. % water, more particularly at least about 90 wt. % water,such as at least about 95 wt. % water, for example at least about 99 wt.% water.

Conveniently, the organic phase produced in (d) comprises up to about 95wt. % C₅+ hydrocarbons, or up to about 75 wt. % C₅+ hydrocarbons, or upto about 60 wt. % C₅+ hydrocarbons, or up to about 50 wt. % C₅+hydrocarbons. Typically, the organic phase comprises at least about 1wt. % C₅+ saturates, such as at least about 5 wt. % C₅+ saturates, forexample at least about 10 wt. % C₅+ saturates, and generally no greaterthan about 60 wt. % C₅+ saturates, more specifically no greater thanabout 40 wt. % C₅+ saturates, such as no greater than about 30 wt. % C₅+saturates. Generally, the organic phase comprises at least about 0.1 wt.% aromatics, such as at least about 0.5 wt. % aromatics, including atleast about 1 wt. % aromatics, more particularly at least about at leastabout 2 wt. % aromatics, and typically no greater than about 30 wt. %aromatics, for example no greater than about 20 wt. % aromatics,including no greater than about 10 wt. % aromatics, such as no greaterthan about 5 wt. % aromatics. Conveniently, the organic phase comprisesat least about 0.01 wt. % benzene, such as at least about 0.05 wt. %benzene, including at least about 0.1 wt. % benzene, and typically nogreater than about 3 wt. % benzene, for example no greater than about 2wt. % benzene, including no greater than about 1 wt. % benzene.

Conveniently, the aqueous phase comprises at least about 25 wt. % water,for example at least about 40 wt. % water, such as at least about 50 wt.% water, more particularly at least about 60 wt. % water.

Conveniently, the aqueous phase comprises at least about 1 wt. % of theat least one oxygenate, for example at least about 10 wt. % of the atleast one oxygenate, such as at least about 20 wt. % of the at least oneoxygenate, and generally no greater than about 60 wt. % of the at leastone oxygenate, such as no greater than about 50 wt. % of the at leastone oxygenate, including no greater than about 35 wt. % of the at leastone oxygenate.

Conveniently, the aqueous phase comprises at least about 1 wt. % of C₂to C₆ carbonyls, for example at least about 10 wt. % of C₂ to C₆carbonyls, such as at least about 20 wt. % of C₂ to C₆ carbonyls, andgenerally no greater than about 60 wt. % of C₂ to C₆ carbonyls, such asno greater than about 50 wt. % of C₂ to C₆ carbonyls, including nogreater than about 35 wt. % of C₂ to C₆ carbonyls.

Conveniently, said contacting (d) is conducted within said liquid-liquidcontacting device at a pressure of from about 170 kPaa (10 psig) toabout 2514 kpaa (350 psig), such as from about 446 kPaa (50 psig) toabout 1480 kpaa (200 psig). Conveniently, said contacting (d) isconducted within said liquid-liquid contacting device at a temperatureof from about 1° C. (34° F.) to about 54° C. (130° F.), for example fromabout 21° C. (70° F.) to about 43° C. (110° F.).

In one embodiment, the process further comprises fractionating theaqueous phase produced in (d) into a water-rich fraction and a fractionrich in said at least one oxygenated hydrocarbon. If desired, at leastpart of said fraction rich in said at least one oxygenated hydrocarbonis recycled to said oxygenate to olefin conversion reaction. Further, ifdesired, at least a part of the water-rich fraction can be used as atleast a portion of the liquid water-containing stream for liquid-liquidcontacting.

In a further aspect, the invention resides in a process for producingolefins comprising:

-   -   (a) providing a vapor product stream from an oxygenate to olefin        reaction comprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least        one oxygenate and water;    -   (b) cooling the vapor product stream to remove water therefrom        and produce a first vapor effluent stream;    -   (c) compressing and cooling the first vapor effluent stream to        produce a second effluent stream that is at least partially in        the vapor state;    -   (d) washing at least part of the second effluent stream with a        liquid alcohol-containing stream to remove at least a portion of        at least one oxygenate from the second effluent stream in a wash        liquid effluent stream, and produce a wash vapor effluent stream        comprising C₂ to C₄ olefins, the wash liquid effluent stream        further comprising C₅+ hydrocarbons and alcohol from the liquid        alcohol-containing stream; and    -   (e) contacting at least a portion of the wash liquid effluent        stream with a liquid water-containing stream in a liquid-liquid        contacting device to at least partially separate said wash        liquid effluent stream, or portion thereof, into an aqueous        phase rich in said at least one oxygenate and said alcohol from        the liquid alcohol-containing stream, and an organic phase rich        in said C₅+ hydrocarbons.

Conveniently, the liquid alcohol-containing stream comprises methanoland/or ethanol, and preferably methanol.

Conveniently, the second effluent stream produced in (c) has a pressureranging from about 446 kPaa (50 psig) to about 2514 kPaa (350 psig),such as from about 791 kPaa (100 psig) to about 2100 kPaa (290 psig),for example from about 1066 kPaa (140 psig) to about 1342 kPaa (180psig). Generally, the second effluent stream produced in (c) has atemperature ranging from about 20° C. (68° F.) to about 54° C. (130°F.), such as from about 32° C. (90° F.) to about 43° C. (110° F.).

Conveniently, the wash liquid effluent stream produced in (d) has apressure ranging from about 446 kPaa (50 psig) to about 2514 kPaa (350psig), such as from about 791 kPaa (100 psig) to about 2100 kPaa (290psig), for example from about 1066 kPaa (140 psig) to about 1342 kPaa(180 psig). Generally, the wash liquid effluent stream produced in (d)has a temperature ranging from about 20° C. (68° F.) to about 54° C.(130° F.), such as from about 32° C. (90° F.) to about 43° C. (110° F.).

Conveniently, the wash liquid effluent stream produced in (d) comprisesup to about 90 wt. % C₅+ hydrocarbon, or up to about 70 wt. % C₅+hydrocarbon, or up to about 50 C₅+ hydrocarbon, or up to about 30 wt. %C₅+ hydrocarbon. Typically, the wash liquid effluent stream comprises atleast about 1 wt. % C₅+ hydrocarbon, such as at least about 5 wt. % C₅+hydrocarbon, for example at least about about 10 wt. % C₅+ hydrocarbon,more particularly at least about 20 wt. % C₅+ hydrocarbon. Conveniently,the wash liquid effluent stream comprises no more than about 40 wt. %aromatics, such as no more than about 30 wt. % aromatics, morespecifically no more than about 20 wt. % aromatics, for example no morethan about 10 wt. % aromatics, including no more than about 5 wt. %aromatics, and generally at least about 0.1 wt. % aromatics, for exampleat least about 1 wt. % aromatics, such as a least about 2 wt. %aromatics, more particularly at least about 4 wt. % aromatics.

Conveniently, the wash liquid effluent stream produced in (d) comprisesno more than about 10 wt. % benzene, such as no more than about 5 wt. %benzene, for example no more than about 1 wt. % benzene, including nomore than about 0.5 wt. % benzene, more specifically no more than about0.1 wt. % benzene. Generally, the wash liquid effluent stream comprisesno more than about 50 wt. % C₅+ saturates, such as no more than about 30wt. % C₅+ saturates, including no more than about 10 wt. % C₅+saturates, for example no more than about 5 wt. % C₅+ saturates, andtypically at least about 0.1 wt. % C₅+ saturates, for example at leastabout 1 wt. % C₅+ saturates, such as a least about 2 wt. % C₅+saturates, more particularly at least about 4 wt. % C₅+ saturates.

In one embodiment, the wash liquid effluent stream produced in (d)comprises at least about 1 wt. % oxygenate, such as at least about 5 wt.% oxygenate, for example at least about 10 wt. % oxygenate, morespecifically at least about 20 wt. % oxygenate, including at least about30 wt. % oxygenate.

Conveniently, the wash liquid effluent stream produced in (d) comprisesat least about 5 wt. %, such as at least about 10 wt. %, for example atleast about 20 wt. %, more particularly at least about 30 wt. %, alcoholfrom the liquid alcohol-containing stream. Suitably, the wash liquideffluent stream comprises no greater than about 90 wt. %, for example nogreater than about 75 wt. %, such as no greater than about 60 wt. %alcohol from the liquid alcohol-containing stream.

Conveniently, the wash liquid effluent stream produced in (d) comprisesat least about 0.1 wt. % C₂ to C₆ carbonyls, or at least about 1 wt. %C₂ to C₆ carbonyls, or at least about 2 wt. % C₂ to C₆ carbonyls, or atleast about 5 wt. % C₂ to C₆ carbonyls, or at least about 10 wt. % C₂ toC₆ carbonyls.

In one embodiment the compression and cooling (c) comprises compressingthe first vapor effluent stream and cooling the compressed first vaporeffluent stream to produce a first condensed liquid effluent stream anda first residual vapor effluent stream. The first residual vaporeffluent stream is compressed and cooled to produce a second effluentstream that is at least partially in the vapor state, and the secondeffluent stream is provided for the washing (d). Optionally, the secondeffluent stream is segregated into a second condensed liquid effluentstream and a second residual vapor effluent stream, with the secondresidual vapor effluent stream being provided for the washing (d).

In an embodiment, the wash liquid effluent stream produced in (d) isexposed to one or more reductions in pressure to form a wash flashliquid effluent stream and a wash flash vapor effluent stream, and thewash flash liquid effluent stream is provided as the wash liquideffluent stream for contacting (e). In a modification, at least aportion of the wash flash vapor effluent stream is provided along withthe first vapor effluent stream for compression and cooling (c).Optionally, at least a portion of the wash flash vapor effluent isprovided for compression and cooling along with the first residual vaporeffluent. The pressure of the wash flash liquid effluent stream will belower than that of the wash liquid effluent stream from which it isderived, and conveniently ranges from about 108 kPaa (1 psig) to about2169 kPaa (300 psig), such as from about 170 kPaa (10 psig) to about1480 kPaa (200 psig).

In yet another aspect, the invention resides in a process for producingolefins comprising:

-   -   (a) providing a vapor product stream from an oxygenate to olefin        reaction comprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least        one oxygenate and water;    -   (b) cooling the vapor product stream to remove water therefrom        and produce a first vapor effluent stream;    -   (c) compressing and cooling the first vapor effluent stream to        produce a condensed liquid effluent stream comprising C5+        hydrocarbons and at least one oxygenate and a residual vapor        effluent stream comprising C₂ to C₄ olefins;    -   (d) washing at least part of the residual vapor effluent stream        with a liquid alcohol-containing stream to produce a wash vapor        effluent stream comprising C₂ to C₄ olefins, and a wash liquid        effluent stream comprising said at least one oxygenate and said        C₅+ hydrocarbons; and    -   (e) contacting at least a portion of the condensed liquid        effluent stream produced in (c) and at least a portion of the        wash liquid effluent stream produced in (d) with a liquid        water-containing stream in a liquid-liquid contacting device to        at least partially separate said condensed liquid effluent        stream produced in (c) and saud wash liquid effluent stream        produced in (d), or portions thereof, into an aqueous phase rich        in said at least one oxygenate and alcohol contained in the        liquid alcohol containing stream, and an organic phase rich in        said C₅+ hydrocarbons.

In one embodiment, said condensed liquid effluent stream in (c) and saidwash liquid effluent stream in (d), or portions thereof, are combined,and said combined stream, or a portion thereof, is provided forcontacting (e).

Alternatively, the condensed liquid effluent stream in (c) and the washliquid effluent stream in (d), or portions thereof, are combined, andthe combined stream, or a portion thereof, is exposed to one or morereductions in pressure to form a flash liquid effluent stream. The flashliquid effluent stream is provided as the portion of the wash liquideffluent stream for contacting (e).

Conveniently, the compression and cooling (c) comprises compressing thefirst vapor effluent stream, and cooling the compressed first vaporeffluent stream to produce a first condensed liquid effluent stream anda first remaining vapor effluent stream. The first remaining vaporeffluent stream is compressed and cooled to produce a second effluentstream that is at least partially in the vapor state, said secondeffluent stream being provided for said washing (d). Optionally, thesecond effluent stream is segregated into a second condensed liquideffluent stream and a second residual vapor effluent stream, with thesecond residual vapor effluent stream is provided for washing (d).

In a modification, the first condensed liquid effluent stream, secondcondensed liquid effluent stream or wash liquid effluent stream, orportions thereof, is exposed to one or more reductions in pressure toform a flash liquid effluent stream, wherein said flash liquid effluentstream is provided as at least a portion of the condensed liquideffluent stream and wash liquid effluent stream for contacting (e).

Optionally, one or more of the liquid effluent streams, or portionsthereof are mixed prior to the reduction in pressure. In a more specificembodiment of this type, the second condensed liquid effluent stream andthe wash liquid effluent stream, or portions thereof, are exposed to areduction in pressure along with the compressed first vapor effluentstream to produce a first residual vapor effluent stream and a commonfirst condensed liquid effluent stream and first flash liquid effluentstream. This common first condensed liquid effluent stream and firstflash liquid effluent stream is exposed to a further reduction inpressure to produce a second flash liquid effluent stream that providedas at least a portion of the condensed liquid effluent stream and washliquid effluent stream for contacting (e).

As used herein, the term “C_(x) hydrocarbon” indicates aliphatic,olefin, diolefin, acetylene, or cyclic variations thereof, or aromatichydrocarbon molecules having the number of carbon atoms represented bythe subscript “x” Similarly, the term “C_(x)-containing stream” meansthe stream contains C_(x) hydrocarbon. The more specific molecule isrepresented by a more explicit term in place of “hydrocarbon”, so that,for example, “C₄ olefin” indicates butene-1, or butene-2, or isobutene,or combinations thereof. The term “C_(x)+hydrocarbons” indicates thosemolecules noted above having the number of carbon atoms represented bythe subscript “x” or greater. For example, “C₄+hydrocarbons” wouldinclude C₄, C₅ and higher carbon number hydrocarbons. Similarly“C_(x)-hydrocarbons” indicates those molecules noted above having thenumber of carbon atoms represented by the subscript “x” or fewer. Asused herein, hydrocarbons do not contain an oxygen molecule and thus arenot to be confused with the term oxygenate or its various more specificforms, such as alcohol, ether, aldehyde, ketone or carbonyl.

As used herein, the term “aromatic” has the classical chemistry meaningof a hydrocarbon molecule containing the six-carbon ring characteristicof the benzene series and related organic groups. Examples of aromaticsinclude, but are not limited to single ring compounds such as benzene,and their alkyl substituted forms such as toluene, xylenes such asortho-xylene and para-xylene, cumene and durene. Aromatics also includescondensed aromatic ring molecules such as naphthalene and alkylsubstituted forms thereof. An oxygen atom may be present in an aromaticmolecule, such as phenol, but such an aromatic specie is not to beconfused with the term oxygenate as used herein. Further, an aromaticmolecule is considered to be within the potential scope of the moregeneral term C₅+ hydrocarbons.

As used herein, the term “C₂ to C₆ carbonyl compounds” is defined asmeaning one or more molecules containing from 2 to 6 carbon atoms thatfurther comprise at least one oxygen atom in an aldehyde (oxygen thathas a double bond to a carbon atom that in turn has a single bond to oneother carbon atom and one hydrogen atom) or ketone (oxygen that hasdouble bond to a carbon atom that in turn has a single bond to each oftwo other carbon atoms) moiety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flow diagram illustrating a process according to afirst example of the invention.

FIG. 2 is a schematic flow diagram illustrating a process according to asecond example of the invention.

FIG. 3 is a schematic flow diagram illustrating a process according to athird example of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Molecular Sieves and Catalysts Thereof for Use in OTO Conversion

Molecular sieves suited to use for converting oxygenates to olefins(OTO) have various chemical and physical, framework, characteristics.Molecular sieves have been well classified by the Structure Commissionof the International Zeolite Association according to the rules of theIUPAC Commission on Zeolite Nomenclature. A framework-type describes theconnectivity, topology, of the tetrahedrally coordinated atomsconstituting the framework, and making an abstraction of the specificproperties for those materials. Framework-type zeolite and zeolite-typemolecular sieves for which a structure has been established, areassigned a three letter code and are described in the Atlas of ZeoliteFramework Types, 5th edition, Elsevier, London, England (2001), which isherein fully incorporated by reference.

Non-limiting examples of these molecular sieves are the small poremolecular sieves of a framework-type selected from the group consistingof AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS, CHA, CHI, DAC, DDR, EDI,ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU, PHI, RHO, ROG, THO, andsubstituted forms thereof, the medium pore molecular sieves of aframework-type selected from the group consisting of AFO, AEL, EUO, HEU,FER, MEL, MFI, MTW, MTT, TON, and substituted forms thereof; and thelarge pore molecular sieves of a framework-type selected from the groupconsisting of EMT, FAU, and substituted forms thereof. Other molecularsieves have a framework-type selected from the group consisting of ANA,BEA, CFI, CLO, DON, GIS, LTL, MER, MOR, MWW and SOD. Non-limitingexamples of the preferred molecular sieves, particularly for convertingan oxygenate containing feedstock into olefin(s), include those having aframework-type selected from the group consisting of AEL, AFY, BEA, CHA,EDI, FAU, FER, GIS, LTA, LTL, MER, MFI, MOR, MTT, MWW, TAM and TON. Inone embodiment, the molecular sieve used in the process of the inventionhas an AEI topology or a CHA topology, or a combination thereof,preferably a CHA topology.

Molecular sieve materials all have 3-dimensional, four-connectedframework structure of corner-sharing TO₄ tetrahedra, where T is anytetrahedrally coordinated cation. These molecular sieves are typicallydescribed in terms of the size of the ring that defines a pore, wherethe size is based on the number of T atoms in the ring. Otherframework-type characteristics include the arrangement of rings thatform a cage, and when present, the dimension of channels, and the spacesbetween the cages. See van Bekkum, et al., Introduction to ZeoliteScience and Practice, Second Completely Revised and Expanded Edition,Volume 137, pages 1-67, Elsevier Science, B.V., Amsterdam, Netherlands(2001).

The small, medium and large pore molecular sieves have from a 4-ring toa 12-ring or greater framework-type. In one embodiment, the molecularsieves used herein have 8-, 10- or 12-ring structures or larger and anaverage pore size in the range of from about 3 Å to 15 Å. Moretypically, the molecular sieves utilized in the invention, such assilicoaluminophosphate molecular sieves, have 8-rings and an averagepore size less than about 5 Å, such as in the range of from 3 Å to about5 Å, for example from 3 Å to about 4.5 Å, particularly from 3.5 Å toabout 4.2 Å.

Molecular sieves used herein typically have two or more [SiO₄], [AlO₄]and/or [PO₄] tetrahedral units. These silicon, aluminum and/orphosphorous based molecular sieves and metal containing silicon,aluminum and phosphorous based molecular sieves have been described indetail in numerous publications including for example, U.S. Pat. No.4,567,029 (MeAPO where Me is Mg, Mn, Zn, or Co), U.S. Pat. No. 4,440,871(SAPO), European Patent Application EP-A-0 159 624 (ELAPSO where El isAs, Be, B, Cr, Co, Ga, Ge, Fe, Li, Mg, Mn, Ti or Zn), U.S. Pat. No.4,554,143 (FeAPO), U.S. Pat. Nos. 4,822,478, 4,683,217, 4,744,885(FeAPSO), EP-A-0 158 975 and U.S. Pat. No. 4,935,216 (ZnAPSO, EP-A-0 161489 (CoAPSO), EP-A-0 158 976 (ELAPO, where EL is Co, Fe, Mg, Mn, Ti orZn), U.S. Pat. No. 4,310,440 (AlPO₄), EP-A-0 158 350 (SENAPSO), U.S.Pat. No. 4,973,460 (LiAPSO), U.S. Pat. No. 4,789,535 (LiAPO), U.S. Pat.No. 4,992,250 (GeAPSO), U.S. Pat. No. 4,888,167 (GeAPO), U.S. Pat. No.5,057,295 (BAPSO), U.S. Pat. No. 4,738,837 (CrAPSO), U.S. Pat. Nos.4,759,919, and 4,851,106 (CrAPO), U.S. Pat. Nos. 4,758,419, 4,882,038,5,434,326 and 5,478,787 (MgAPSO), U.S. Pat. No. 4,554,143 (FeAPO), U.S.Pat. No. 4,894,213 (AsAPSO), U.S. Pat. No. 4,913,888 (AsAPO), U.S. Pat.Nos. 4,686,092, 4,846,956 and 4,793,833 (MnAPSO), U.S. Pat. Nos.5,345,011 and 6,156,931 (MnAPO), U.S. Pat. No. 4,737,353 (BeAPSO), U.S.Pat. No. 4,940,570 (BeAPO), U.S. Pat. Nos. 4,801,309, 4,684,617 and4,880,520 (TiAPSO), U.S. Pat. Nos. 4,500,651, 4,551,236 and 4,605,492(TiAPO), U.S. Pat. No. 4,824,554, 4,744,970 (CoAPSO), U.S. Pat. No.4,735,806 (GaAPSO) EP-A-0 293 937 (QAPSO, where Q is framework oxideunit [QO2]), as well as U.S. Pat. Nos. 4,567,029, 4,686,093, 4,781,814,4,793,984, 4,801,364, 4,853,197, 4,917,876, 4,952,384, 4,956,164,4,956,165, 4,973,785, 5,241,093, 5,493,066 and 5,675,050, all of whichare herein fully incorporated by reference.

Other molecular sieves include those described in EP-0 888 187 B1(microporous crystalline metallophosphates, SAPO₄ (UIO-6)), U.S. Pat.No. 6,004,898 (molecular sieve and an alkaline earth metal), U.S. patentapplication Ser. No. 09/511,943 filed Feb. 24, 2000 (integratedhydrocarbon co-catalyst), International Patent Publication No. WO01/64340 published Sep. 7, 2001 (thorium containing molecular sieve),and R. Szostak, Handbook of Molecular Sieves, Van Nostrand Reinhold, NewYork, N.Y. (1992), which are all herein fully incorporated by reference.

The more preferred silicon, aluminum and/or phosphorous containingmolecular sieves include aluminophosphate (ALPO) molecular sieves,silicoaluminophosphate (SAPO) molecular sieves and substituted,preferably metal substituted, forms thereof. The most preferredmolecular sieves are SAPO molecular sieves, and metal substituted SAPOmolecular sieves. In an embodiment, the metal is an alkali metal ofGroup IA of the Periodic Table of Elements, an alkaline earth metal ofGroup IIA of the Periodic Table of Elements, a rare earth metal of GroupIIIB, including the Lanthanides: lanthanum, cerium, praseodymium,neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium,erbium, thulium, ytterbium and lutetium; and scandium or yttrium of thePeriodic Table of Elements, a transition metal of Groups IVB, VB, VIB,VIIB, VIIIB, and IB of the Periodic Table of Elements, or mixtures ofany of these metal species. In one preferred embodiment, the metal isselected from the group consisting of Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn,Ni, Sn, Ti, Zn and Zr, and mixtures thereof. In another preferredembodiment, these metal atoms discussed above are inserted into theframework of a molecular sieve through a tetrahedral unit, such as[MeO₂], and carry a net charge depending on the valence state of themetal substituent. For example, in one embodiment, when the metalsubstituent has a valence state of +2, +3, +4, +5, or +6, the net chargeof the tetrahedral unit is between −2 and +2.

In one embodiment, the molecular sieve, as described in many of the U.S.Patents mentioned above, is represented by the empirical formula, on ananhydrous basis:mR:(M_(x)Al_(y)P_(z))O₂wherein R represents at least one templating agent, preferably anorganic templating agent; m is the number of moles of R per mole of(MAl_(y)P_(z))O₂ and m has a value from 0 to 1, preferably 0 to 0.5, andmost preferably from 0 to 0.3; x, y, and z represent the mole fractionof Al, P and M as tetrahedral oxides, where M is a metal selected fromone of Group IA, IIA, IB, IIIB, IVB, VB, VIB, VIIB, VIIIB andLanthanides of the Periodic Table of Elements, preferably M is selectedfrom one of the group consisting of Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni,Sn, Ti, Zn and Zr. In an embodiment, m is greater than or equal to 0.2,and x, y and z are greater than or equal to 0.01.

In another embodiment, m is greater than 0.1 to about 1, x is greaterthan 0 to about 0.25, y is in the range of from 0.4 to 0.5, and z is inthe range of from 0.25 to 0.5, more preferably m is from 0.15 to 0.7, xis from 0.01 to 0.2, y is from 0.4 to 0.5, and z is from 0.3 to 0.5.

Non-limiting examples of SAPO and ALPO molecular sieves of the inventioninclude one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Pat. No. 6,162,415), SAPO-47,SAPO-56, ALPO-5, ALPO-11, ALPO-18, ALPO-31, ALPO-34, ALPO-36, ALPO-37,ALPO-46, and metal containing molecular sieves thereof. The morepreferred zeolite-type molecular sieves include one or a combination ofSAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-56, ALPO-18 and ALPO-34, evenmore preferably one or a combination of SAPO-18, SAPO-34, ALPO-34 andALPO-18, and metal containing molecular sieves thereof, and mostpreferably one or a combination of SAPO-34 and ALPO-18, and metalcontaining molecular sieves thereof.

In an embodiment, the molecular sieve is an intergrowth material havingtwo or more distinct phases of crystalline structures within onemolecular sieve composition. In particular, intergrowth molecular sievesare described in the U.S. patent application Publication No.2002/0165089 published Nov. 7, 2002 and International Patent PublicationNo. WO 98/15496 published Apr. 16, 1998, both of which are herein fullyincorporated by reference. In another embodiment, the molecular sievecomprises at least one intergrown phase of AEI and CHA framework-types.For example, SAPO-18, ALPO-18 and RUW-18 have an AEI framework-type, andSAPO-34 has a CHA framework-type.

The molecular sieves useful for oxygenates to olefins conversionprocesses are synthesized and then made or formulated into catalysts bycombining the synthesized molecular sieves with a binder and/or a matrixmaterial to form a molecular sieve catalyst composition. This molecularsieve catalyst composition is formed into useful shaped and sizedparticles by well-known techniques such as spray drying, pelletizing,extrusion, and the like.

Oxygenate to Olefins (OTO) Process

The feedstock to an oxygenate to olefins process comprises one or moreoxygenates, more specifically, one or more organic compound(s)containing at least one oxygen atom. Typically, the oxygenate in thefeedstock comprises one or more alcohol(s), generally aliphaticalcohol(s) where the aliphatic moiety of the alcohol(s) has from 1 to 20carbon atoms, such as from 1 to 10 carbon atoms, and conveniently from 1to 4 carbon atoms. The alcohols useful as feedstock in an oxygenate toolefins process include lower straight and branched chain aliphaticalcohols and their unsaturated counterparts.

Non-limiting examples of suitable oxygenates include methanol, ethanol,n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethylether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethylketone, acetic acid, and mixtures thereof. Typically, the feedstock isselected from one or more of methanol, ethanol, dimethyl ether anddiethyl ether, especially methanol and dimethyl ether, and preferablymethanol.

In addition to the oxygenate component, such as methanol, the feedstockmay contains one or more diluent(s), which are generally non-reactive tothe feedstock or molecular sieve catalyst composition and are typicallyused to reduce the concentration of the feedstock. Non-limiting examplesof diluents include helium, argon, nitrogen, carbon monoxide, carbondioxide, water, essentially non-reactive paraffins (especially alkanessuch as methane, ethane, and propane), essentially non-reactive aromaticcompounds, and mixtures thereof. The most preferred diluents are waterand nitrogen, with water being particularly preferred.

The diluent, for example water, may be used either in a liquid or avapor form, or a combination thereof. The diluent may be either addeddirectly to the feedstock entering a reactor or added directly to thereactor, or added with the molecular sieve catalyst composition.Diluent(s) may comprise from about 1 mole % to about 99 mole % of thetotal feedstock.

In the OTO process, the various feedstocks discussed above, particularlya feedstock containing an alcohol, are converted over a molecular sievecatalyst, primarily into one or more olefin(s). The olefin(s) or olefinmonomer(s) produced from the feedstock typically have from 2 to 30carbon atoms, such as 2 to 8 carbon atoms, for example 2 to 6 carbonatoms, especially 2 to 4 carbons atoms, and preferably are ethyleneand/or propylene.

The present process can be conducted over a wide range of temperatures,such as in the range of from about 200° C. to about 1000° C., forexample from about 250° C. to about 800° C., including from about 250°C. to about 750° C., conveniently from about 300° C. to about 650° C.,typically from about 350° C. to about 600° C. and particularly fromabout 350° C. to about 550° C.

Similarly, the present process can be conducted over a wide range ofpressures including autogenous pressure. Typically the partial pressureof the feedstock exclusive of any diluent therein employed in theprocess is in the range of from about 0.1 kPaa to about 5 MPaa, such asfrom about 5 kPaa to about 1 MPaa, and conveniently from about 20 kPaato about 500 kPaa.

The weight hourly space velocity (WHSV), defined as the total weight offeedstock excluding any diluents per hour per weight of molecular sievein the catalyst composition, typically ranges from about 1 hr⁻¹ to about5000 hr⁻¹, such as from about 2 hr⁻¹ to about 3000 hr⁻¹, for examplefrom about 5 hr⁻¹ to about 1500 hr⁻¹, and conveniently from about 10hr⁻¹ to about 1000 hr⁻¹. In one embodiment, the WHSV is greater than 20hr⁻¹ and, where feedstock contains methanol and/or dimethyl ether, is inthe range of from about 20 hr⁻¹ to about 300 hr⁻¹.

Where the process is conducted in a fluidized bed, the superficial gasvelocity (SGV) of the feedstock including diluent and reaction productswithin the reactor system, and particularly within a riser reactor(s),is at least 0.1 meter per second (m/sec), such as greater than 0.5m/sec, such as greater than 1 m/sec, for example greater than 2 m/sec,conveniently greater than 3 m/sec, and typically greater than 4 m/sec.

The process of the invention is conveniently conducted as a fixed bedprocess, or more typically as a fluidized bed process (including aturbulent bed process), such as a continuous fluidized bed process, andparticularly a continuous high velocity fluidized bed process.

The process can take place in a variety of catalytic reactors such ashybrid reactors that have a dense bed or fixed bed reaction zones and/orfast fluidized bed reaction zones coupled together, circulatingfluidized bed reactors, riser reactors, and the like. Suitableconventional reactor types are described in for example U.S. Pat. No.4,076,796, U.S. Pat. No. 6,287,522 (dual riser), and FluidizationEngineering, D. Kunii and O. Levenspiel, Robert E. Krieger PublishingCompany, New York, N.Y. 1977, which are all herein fully incorporated byreference.

The preferred reactor types are riser reactors generally described inRiser Reactor, Fluidization and Fluid-Particle Systems, pages 48 to 59,F. A. Zenz and D. F. Othmer, Reinhold Publishing Corporation, New York,1960, and U.S. Pat. No. 6,166,282 (fast-fluidized bed reactor), and U.S.patent application Ser. No. 09/564,613 filed May 4, 2000 (multiple riserreactor), which are all herein fully incorporated by reference.

In one practical embodiment, the process is conducted as a fluidized bedprocess or high velocity fluidized bed process utilizing a reactorsystem, a regeneration system and a recovery system.

In such a process the reactor system would conveniently include a fluidbed reactor system having a first reaction zone within one or more riserreactor(s) and a second reaction zone within at least one disengagingvessel, typically comprising one or more cyclones. In one embodiment,the one or more riser reactor(s) and disengaging vessel are containedwithin a single reactor vessel. Fresh feedstock, preferably containingone or more oxygenates, optionally with one or more diluent(s), is fedto the one or more riser reactor(s) into which a molecular sievecatalyst composition or coked version thereof is introduced. In oneembodiment, prior to being introduced to the riser reactor(s), themolecular sieve catalyst composition or coked version thereof iscontacted with a liquid, preferably water or methanol, and/or a gas, forexample, an inert gas such as nitrogen.

In an embodiment, the amount of liquid feedstock fed separately orjointly with a vapor feedstock, to the reactor system is in the range offrom 0.1 weight percent to about 85 weight percent, such as from about 1weight percent to about 75 weight percent, for example from about 5weight percent to about 65 weight percent based on the total weight ofthe feedstock including any diluent contained therein. The liquid andvapor feedstocks are preferably of similar or the same composition, orcontain varying proportions of the same or different feedstock with thesame or different diluent.

The feedstock entering the reactor system is preferably converted,partially or fully, in the first reactor zone into a gaseous productstream that enters the disengaging vessel along with the coked catalystcomposition. In the preferred embodiment, cyclone(s) are provided withinthe disengaging vessel to separate the coked catalyst composition fromthe gaseous product stream containing one or more olefin(s) within thedisengaging vessel. Although cyclones are preferred, gravity effectswithin the disengaging vessel can also be used to separate the catalystcomposition from the gaseous product stream. Other methods forseparating the catalyst composition from the gaseous product streaminclude the use of plates, caps, elbows, and the like.

In one embodiment, the disengaging vessel includes a stripping zone,typically in a lower portion of the disengaging vessel. In the strippingzone the coked catalyst composition is contacted with a gas, preferablyone or a combination of steam, methane, carbon dioxide, carbon monoxide,hydrogen, or an inert gas such as argon, preferably steam, to recoveradsorbed hydrocarbons from the coked catalyst composition that is thenintroduced to the regeneration system.

The coked catalyst composition is withdrawn from the disengaging vesseland introduced to the regeneration system. The regeneration systemcomprises a regenerator where the coked catalyst composition iscontacted with a regeneration medium, preferably a gas containingoxygen, under conventional regeneration conditions of temperature,pressure and residence time.

Non-limiting examples of suitable regeneration media include one or moreof oxygen, O₃, SO₃, N₂O, NO, NO₂, N₂O₅, air, air diluted with nitrogenor carbon dioxide, oxygen and water (U.S. Pat. No. 6,245,703), carbonmonoxide arid/or hydrogen. Suitable regeneration conditions are thosecapable of burning coke from the coked catalyst composition, preferablyto a level less than 0.5 weight percent based on the total weight of thecoked molecular sieve catalyst composition entering the regenerationsystem. For example, the regeneration temperature may be in the range offrom about 200° C. to about 1500° C., such as from about 300° C. toabout 1000° C., for example from about 450° C. to about 750° C., andconveniently from about 550° C. to 700° C. The regeneration pressure maybe in the range of from about 15 psia (103 kPaa) to about 500 psia (3448kPaa), such as from about 20 psia (138 kPaa) to about 250 psia (1724kPaa), including from about 25 psia (172 kPaa) to about 150 psia (1034kPaa), and conveniently from about 30 psia (207 kPaa) to about 60 psia(414 kPaa).

The residence time of the catalyst composition in the regenerator may bein the range of from about one minute to several hours, such as fromabout one minute to 100 minutes, and the volume of oxygen in theregeneration gas may be in the range of from about 0.01 mole percent toabout 5 mole percent based on the total volume of the gas.

The burning of coke in the regeneration step is an exothermic reaction,and in an embodiment, the temperature within the regeneration system iscontrolled by various techniques in the art including feeding a cooledgas to the regenerator vessel, operated either in a batch, continuous,or semi-continuous mode, or a combination thereof. A preferred techniqueinvolves withdrawing the regenerated catalyst composition from theregeneration system and passing it through a catalyst cooler to form acooled regenerated catalyst composition. The catalyst cooler, in anembodiment, is a heat exchanger that is located either internal orexternal to the regeneration system. Other methods for operating aregeneration system are disclosed in U.S. Pat. No. 6,290,916(controlling moisture), which is herein fully incorporated by reference.

The regenerated catalyst composition withdrawn from the regenerationsystem, preferably from a catalyst cooler, is combined with a freshmolecular sieve catalyst composition and/or re-circulated molecularsieve catalyst composition and/or feedstock and/or fresh gas or liquids,and returned to the riser reactor(s). In one embodiment, the regeneratedcatalyst composition withdrawn from the regeneration system is returnedto the riser reactor(s) directly, preferably after passing through acatalyst cooler. A carrier, such as an inert gas, feedstock vapor, steamor the like, may be used, semi-continuously or continuously, tofacilitate the introduction of the regenerated catalyst composition tothe reactor system, preferably to the one or more riser reactor(s).

By controlling the flow of the regenerated catalyst composition orcooled regenerated catalyst composition from the regeneration system tothe reactor system, the optimum level of coke on the molecular sievecatalyst composition entering the reactor is maintained. There are manytechniques for controlling the flow of a catalyst composition describedin Michael Louge, Experimental Techniques, Circulating Fluidized Beds,Grace, Avidan and Knowlton, eds., Blackie, 1997 (336-337), which isherein incorporated by reference.

Coke levels on the catalyst composition are measured by withdrawing thecatalyst composition from the conversion process and determining itscarbon content. Typical levels of coke on the molecular sieve catalystcomposition, after regeneration, are in the range of from 0.01 weightpercent to about 15 weight percent, such as from about 0.1 weightpercent to about 10 weight percent, for example from about 0.2 weightpercent to about 5 weight percent, and conveniently from about 0.3weight percent to about 2 weight percent based on the weight of themolecular sieve.

The gaseous product stream is withdrawn from the disengaging system andpassed to a recovery system for separating and purifying the olefins andother useful components in the product stream.

OTO Product Recovery Process

The vapor product stream from the oxygenate to olefin conversion processdescribed above is a complex mixture comprising C₂ to C₄ olefins, C₅+hydrocarbons, unconverted oxygenates, by-product oxygenates (includingC₂ to C₆ aldehydes and ketones), heavier hydrocarbons (includingaromatics, such as benzene) and large amounts of water.

On leaving the OTO reactor system, the vapor product stream is atreaction temperature and pressure and hence is initially cooled in aquench device. The quench device removes heat from the vapor productstream, and may comprise a traditional indirect heat exchanger, forexample using cooling water or air on the shell or open side with thevapor product stream within tubes, or a direct contact device such as atraditional quench tower employing water as the quench medium. As aresult of this cooling, water from the vapor product stream willcondense to the liquid phase while the bulk of the hydrocarbons remainin the vapor phase. The liquid water phase is then separated from thevapor phase by conventional means. In an indirect heat exchanger, forexample, the water may be collected and removed from a boot provided atthe bottom of the exchanger shell, or the entire condensed vapor productstream may be passed to a vessel, such as a drum, to provide suchliquid-vapor separation. In the quench tower, the water may be collectedin and exit from the bottom of the tower shell. In any case, most of thewater (generally at least 90 wt %) in the vapor product stream iscondensed and is removed from the bottom of the quench device as aliquid water-rich bottoms stream. The light hydrocarbons and lightoxygenates in the product stream are removed from the top of the heatexchanger or quench tower as a first vapor effluent stream at a firstpressure.

The liquid water-rich bottoms stream from the quench device will containvarious other materials in addition to water, such as unreactedoxygenate feedstock, e.g., methanol, and other oxygenates created asbyproducts of the oxygenate to olefins reaction, for example, but notlimited to, ethanol, ethanal, propanal, acetone, butanone, dimethylether, methyl ethyl ether, acetic acid and propionic acid. Theproportions of these oxygenates in the water-rich bottoms stream mayvary widely dependent upon the nature of the oxygenate to olefinreactor, including feedstock, catalyst, WHSV, temperature and pressure.Further, the proportions of these oxygenates in the water-rich bottomsstream may vary widely dependent upon the specifics of the quench tower,such as the pressure, temperature and height of the tower and nature ofthe exchanger or tower internals.

Regardless of the exact composition, the liquid water-rich bottomsstream will need to undergo further processing to provide components inan appropriate state for use or further treatment, e.g., provide a waterstream low enough in organic content for typical water waste treatment,or provide an oxygenate stream low enough in water content for use asfuel or for addition to some point in the oxygenate to olefins processor apparatus. Examples of such treatment can be found in U.S. Pat. Nos.6,121,504, 6,403,854 and 6,459,009 and U.S. patent application Ser. No.10/720,505 filed Nov. 24, 2003.

In one embodiment, the liquid water-rich bottoms stream is directed to awater-oxygenate fractionation tower, e.g., a water-methanolfractionation tower, which is operated to separate methanol and otheroxygenates as an overhead, e.g., greater than about 20 wt % oxygenates(with the balance being largely water), and substantially pure water asa bottoms stream, typically, greater than about 90 wt % water, say,greater than about 95 wt % water, e.g., greater than about 99 wt %water. The overhead product of the fractionation tower, being a fractionrich in at least one oxygenate, can be used for various purposes,including as a feedstock to the OTO reactor along with the primaryoxygenate feedstock. If the fraction rich in at least one oxygenate istaken as a vapor, this provides vaporized methanol/oxygenate feed to thereactor with virtually no incremental heat input beyond that alreadyrequired in the reboiler of the methanol-water fractionation tower, withno incremental heat load in the primary feed vaporization section of theOTO reactor.

The first vapor effluent stream exiting as overhead from the quenchtower is typically at an initial pressure of from about 1 psig to about200 psig (108 to 1480 kPaa), more specifically from about 1 psig toabout 100 psig (108 to 791 kPaa), such as from about 5 psig to about 80psig (136 to 653 kPa), for example from about 5 psig to about 40 psig(136 to 377 kPa). Conveniently, the temperature of the first vaporeffluent stream is at least 80° F. (27° C.), such as at least about 90°F. (32° C.), and generally no more than 130° F. (54° C.), such as nomore than 110° F. (43° C.), for example no more than 100° F. (38° C.).The first vapor effluent stream normally comprises from about 0.5 toabout 5 wt %, such as from about 1 to about 4 wt %, of C₂ to C₆ carbonylcompounds and no more than 10 wt %, for example no more than 5 wt %,such as no more than 2 wt %, water.

After exiting the quench device, the first vapor effluent stream is incommunication with a vapor compression device, conveniently atraditional mechanical reciprocating, centrifugal or axial compressor.Even non-mechanical devices like an ejector, such as a steam ejector,may be used, but are not preferred. The communication typically includespassage through a pipe, potentially further comprising other processelements such as vessels, instrumentation (e.g. a flow metering orificeplate) or valves, such as control valves. Such communication will causea reduction in the pressure of the first vapor effluent prior toreaching the suction of the compression device at a first suctionpressure. Generally the communication path is designed to preserve asmuch pressure of the first vapor effluent stream as practical, thussaving compression costs. The first vapor effluent stream is thencompressed, typically to a pressure that is greater than that of thefirst vapor effluent stream, and cooled, for example in an indirect heatexchanger. Optionally, multiple stages of compression and cooling may beused.

The compression and cooling of the first vapor effluent stream causespartial condensation thereof so as to produce a second effluent streamthat is partially in the vapor state. This second effluent streamcomprises the condensed liquid effluent stream and the residual vaporeffluent stream. The second effluent liquid stream can be separated, forexample in a knock-out drum (into which a heat exchanger for cooling maybe integrated), to provide an individual condensed liquid effluentstream discrete from the residual vapor effluent stream. The residualvapor stream contains the lighter components, including desired C₂ to C₄olefins and some of the lower molecular weight oxygenates, C₂ to C₆carbonyl compounds and C₅+ hydrocarbons, from the first vapor effluentstream. The condensed liquid effluent stream contains heaviercomponents, including a significant proportion of oxygenates, includingunreacted feed, and C₂ to C₆ carbonyl compounds, and C₅+ hydrocarbons.

Where the compression and cooling of the first vapor effluent streamoccurs in a plurality of stages, partial condensation and separation ofcondensed liquid effluent streams and residual vapor effluent streamsfrom the first effluent stream conveniently occurs at each compressionstage, conveniently in a knock-out drum provided after eachcompression/cooling stage. Thus, for example, a first compression andcooling action will provide a first condensed liquid effluent stream anda first residual vapor stream; the first remaining vapor stream is thensubjected to another compression and cooling stage to create a secondliquid effluent stream that is at least partially in the vapor state,that may then be segregated to provide a second liquid effluent streamand a second residual vapor stream. The residual vapor effluent streamand condensed liquid effluent stream exiting the or eachcompression/cooling stage are generally at a pressure greater than thatof the first effluent stream, with a temperature that promotes thedesired extent of partial condensation to generate the desired rates andcompositions of the residual vapor effluent stream and condensed liquideffluent stream.

In one embodiment, the second effluent stream or residual vapor effluentstream (or streams) is subjected to a washing step in which the givenstream is washed with a liquid alcohol-containing stream in avapor-liquid contacting device. This washing step is effective to removeC₂ to C₆ carbonyl compounds from the second effluent stream and residualvapor stream, and produces a wash vapor effluent stream containing thedesired C₂ to C₄ olefins. It also produces a wash liquid effluent streamcomprising the C₂ to C₆ carbonyl compounds and substantial quantities ofC₅+ hydrocarbons and the alcohol from the liquid alcohol containingstream.

Conveniently, said liquid alcohol-containing stream used in the washingstep comprises methanol and/or ethanol, and preferably methanol.Although the methanol employed can contain water and traces (such asless than 2 wt %, or less than 1 wt %, or less than 0.5 wt % or lessthan 0.1 wt %), of other alcohols and hydrocarbons, methanol is moreeffective than water and other alcohols in removing such carbonylspecies from hydrocarbons in a vapor-liquid wash. Generally, therefore,the liquid alcohol-containing stream used in the washing step comprisesat least 75 wt % methanol and less than 25 wt % water, such as at least80 wt % methanol and less than 20 wt % water, for example at least 98 wt% methanol and less than 2 wt % water, such as at least 99 wt % methanoland less than 1 wt % water.

In general, the temperature employed in the washing step should be nomore than 130° F. (54° C.) so as to enhance the oxygenate adsorptioncapacity of the methanol and limit the amount of vaporized methanolexiting the vapor-liquid contacting device with the wash vapor stream.In addition, the temperature employed in the washing step is generallyat least 34° F. (1° C.), so as to mitigate the potential for formingsolids in the system. Conveniently, the temperature of the washing stepis at least 70° F. (21° C.), so as to limit the amount of hydrocarbonsadsorbed by the methanol to acceptable levels, such as at least 80° F.(27° C.), and no more than 120° F. (49° C.), for example no more than110° F. (43° C.). Conveniently, the pressure at which the washing isconducted (also termed herein the “third” pressure) is less than 350psig (2514 kPa), such as less than 200 psig (1480 kPa), for example lessthan 170 psig (1273 kPa), and greater than 100 psig (790 kPa), such asgreater than 140 psig (1066 kPa).

Conveniently, the amount of methanol employed as the liquidalcohol-containing stream in the washing step is at least 0.03 lb (aspure methanol) per lb of the second effluent stream, or residual vaporeffluent stream as appropriate, so as to ensure that there is sufficientmethanol to (1) achieve a desired low level of C₂ to C₆ carbonylcompounds in the C₄ component of wash vapor effluent stream and (2)prevent the formation of a third, aqueous liquid phase in thevapor-liquid contacting device. In addition, the amount of methanolemployed in the washing step is generally no more than 0.5 lb (as puremethanol) per lb of the second effluent stream, or residual vaporeffluent stream, so as to limit the amount of C₂ to C₄ olefins absorbedinto the wash liquid effluent stream. Preferably, the amount of methanolemployed is as at least 0.05 lb, such as at least 0.06 lb, for exampleat least 0.07 lb methanol (as pure methanol) per lb of the secondeffluent stream or residual vapor effluent stream. In addition, theamount of methanol employed is preferably no more than 0.2 lb, such asno more than 0. 15 lb, for example no more than 0.1 lb methanol (as puremethanol) per lb of the second effluent stream or residual vaporeffluent stream.

Conveniently, the vapor-liquid contacting device used in the alcoholwashing step is a countercurrent fractional distillation tower, in whichthe second effluent stream or residual vapor effluent stream is directedinto the bottom of the tower and methanol is directed into the top ofthe tower. The wash vapor effluent stream exits the tower as overheadwhile the wash liquid effluent stream exits as a liquid bottoms stream.

The condensed liquid effluent stream (or streams) derived from the firstvapor effluent stream in the compression/cooling stages, or the washliquid effluent stream from the washing, contain C₅+ hydrocarbons, inaddition to oxygenate species. The C₅+ hydrocarbons will typicallycomprise compounds that are at best unreactive in the OTO reaction, suchas aromatics and saturated hydrocarbons. Thus, if these liquid effluentstreams were recycled to the OTO reactor to utilize the oxygenatescontained therein for the production of additional desired C₂ to C₄olefins, for example either directly or via a water-oxygenatefractionation tower, they would carry these unreactive species withthem. These unreactive species would pass through the OTO reactorlargely intact, and over time build up to unacceptable levels in thestreams moving within the reactor, quench, compression/cooling and washequipment loop, which would detrimentally impact process efficiency andcapacity. In the case of benzene, a build-up to certain concentrationsin a given stream may provoke environmental and hygienic concerns thatwould require expensive means to mitigate.

Thus, in the method of the present invention, one or more of the liquideffluent streams are contacted with a liquid water-containing stream ina liquid-liquid contacting device, such as a liquid-liquid extractioncolumn, so as to at least partially separate the given liquid effluentstream(s) into an aqueous phase rich in said one oxygenate species andan organic phase rich in said C₅+ hydrocarbons. When feeding the washliquid effluent stream to the liquid-liquid contacting device, theorganic phase will also be rich in the alcohol provided in the liquidalcohol-containing stream. This is particularly beneficial when both theprimary oxygenate feed to the OTO reactor and the alcohol provided inthe liquid alcohol-containing stream are methanol.

Conveniently, liquid-liquid contacting of the condensed liquid effluentstream(s) and/or the wash liquid effluent stream in the liquid-liquidcontacting device is effected at a pressure of about atmospheric toabout 600 psig (100 to 4238 kPa), such as about 5 to about 350 psig (135to 2514 kPa) and a temperature of about 35 to about 210° F. (2 to 99°C.), such as about 70 to about 120° F. (21 to 49° C.), such as about 90to about 110° F. (32 to 43° C.). In addition, the liquid-liquidcontacting is conveniently effected by feeding the liquidwater-containing stream to the liquid-liquid contacting device at afirst rate and feeding the given liquid effluent stream to the device ata second rate, wherein the weight ratio of the second rate to the firstrate ranges from about 0.1 to about 10, such as from about 0.2 to about2, for example about 0.3 to about 1.4, such as about 0.6 to about 1.2.Where the oxygenate species in the pertinent liquid effluent streamincludes methanol, the weight ratio of contained methanol in the secondrate to the first rate ranges from about 0.1 to about 1, such as fromabout 0.2 to about 0.7, for example from about 0.3 to about 0.6. Ingeneral, the rate of liquid water-containing stream relative to thegiven liquid effluent stream should be high enough to educe the desiredphases and extract the desired oxygenates into the aqueous phase, butnot so high as to absorb a significant amount of C5+ hydrocarbons,particularly aromatics and saturates, into the aqueous phase merelythrough their natural solubility in water.

In one embodiment, the liquid-liquid contacting device used in the waterwashing step is a countercurrent extraction tower, in which the desiredliquid effluent stream or streams are directed into the bottom of thetower and the liquid water-containing stream is directed into the top ofthe tower. The organic phase exits the tower as a liquid overheadproduct while the aqueous phase exits as a liquid bottoms product.Inside the extraction tower are devices to promote contacting betweenand separation of the two phases, such as perforated trays, or a numberof some type of packing elements, such as Raschig rings, and potentiallydistribution elements such as grids, or dynamic mixing elements such ascirculating blades.

The aqueous phase, now rich in oxygenate and largely depleted ofunreactive species such as aromatics and saturates, can then be fed tothe OTO reactor without the prospect of a build-up of unreactivespecies. In one embodiment, the aqueous phase can be fractionated toprovide a water-rich fraction as a bottoms product and an overheadfraction rich in at least one oxygenate. For example, the aqueous phasecan be fed to a water-oxygenate fractionation tower, taking advantage ofits existence for processing water from the quench device, to allow theoxygenate species to be recovered as an overhead fraction which is richin at least one oxygenate and which can be recycled to the OTO reactor.In another embodiment, at least a portion of the water-rich fractionderived from fractionation of the aqueous phase is used as at least aportion of the liquid water-containing stream for liquid-liquidcontacting. Again, the aqueous phase may be fed to a water-oxygenatefractionation tower, and the liquid water-rich bottoms stream containingthe water-rich fraction from the aqueous phase may be recycled for usein the liquid-liquid contacting.

The organic phase obtained from the liquid-liquid contacting can be usedas fuel, for example to provide heat for the OTO plant. Alternatively,the organic phase can be further processed to recover material therein,for example, heavier oxygenates that may be found in the organic phaseresulting from imperfect separation in the liquid water liquidcontacting device (in general, the higher the molecular weight of anoxygenate, the more it behaves like a hydrocarbon in a liquid-liquidwater contacting action and will exit with the organic phase).

A number of useful optional embodiments exist in the process of thepresent invention for providing the liquid effluent stream of choice tothe liquid-liquid contacting device. For example, one or more liquideffluent streams, or portions thereof, can be provided to differentliquid-liquid contacting devices to provide more than one aqueous phaseand organic phase. Alternatively, one or more liquid effluent streams,or portions thereof, can be provided to a single liquid-liquidcontacting device and provide a single aqueous phase and organic phase.It may be of benefit to mix two or more of the liquid effluent streams,or portions thereof, prior to introducing the mixture to theliquid-liquid contacting device.

In another embodiment, all or a portion of a liquid effluent stream maybe exposed to one or more reductions in pressure to effect avapor-liquid flash. For example, the condensed liquid effluent streamcan be provided to a flash drum at a reduced pressure to produce a flashliquid effluent stream and a flash vapor effluent stream, or the washliquid effluent stream can be provided to a flash drum at a reducedpressure to provide a wash flash liquid effluent stream and a wash flashvapor effluent stream. One or more of these flash liquid effluentstreams, or portions thereof, or mixtures thereof, may then be providedfor liquid-liquid contacting. Optionally, two or more liquid effluentstreams may be provided to a common flash drum, for example a condensedliquid effluent stream and a wash liquid effluent stream, possiblyhaving been mixed beforehand, to provide a common flash liquid effluentstream provided for liquid-liquid contacting. In a modified embodiment,all or a portion of a flash liquid effluent stream, or portions orcombinations of flash liquid effluent streams may be subjected to anadditional reduction in pressure to provide yet another flash liquideffluent stream to be provided for liquid-liquid contacting. Additionalpressure reductions on subsequent flash liquid effluents may continue asdesired.

This manifestation of the invention involving vapor-liquid flashes ofliquid effluent streams may be useful in reducing the amount of lighterhydrocarbons, for example C₂ to C₄ olefins, present in the liquideffluent streams prior to the liquid-liquid contacting, thus potentiallyincreasing their eventual recovery. Thus, in another embodiment of theinvention, the flash vapor effluent generated by exposing a liquideffluent stream, or portions or combinations thereof, to a reduction inpressure is recycled along with another vapor effluent stream, forexample the first vapor effluent stream or the first residual vaporstream depending on the flash conditions and compressor suctionpressures, to a stage of compression and cooling. In this manner, forexample, the desired C₂ to C₄ olefins will build up in the streams inthe compression/cooling and flash equipment loop until they emerge witha residual vapor effluent stream, or the wash vapor effluent stream, forfurther processing and recovery.

The invention will now be more particularly described with reference tothe accompanying drawings.

Referring to FIG. 1, there is illustrated therein a process forconverting an oxygenate to olefins according to a first example of theinvention. An oxygenate feedstock, for example, methanol, is provided inline 10 to oxygenate to olefin reactor 12 for conversion to a vaporproduct stream comprising C₂ to C₄ olefins, C₅+ hydrocarbons, unreactedmethanol and water, which exits the oxygenate to olefin reactor 12 inline 14 at a reaction pressure.

The vapor product stream in line 14 is provided to a cooling device, inthis instance a quench tower 16. The cooling in quench tower 16 servesto condense from the vapor product stream in line 14 a liquid water-richbottoms stream in line 20 near the bottom of quench tower 16, and alsoprovide, from near the top of quench tower 16, a first vapor effluentstream in line 18 at an initial pressure that is no greater than thereaction pressure, and further that comprises no more than 10 wt. %water.

The first vapor effluent stream in line 18 is provided to the suction ofa compressor 22 at a first suction pressure that is no greater than thereaction pressure. The vapor product stream in line 18 is compressed incompressor 22 to produce a compressed first vapor effluent stream inline 24 that is at a second pressure greater than the first suctionpressure. The second vapor effluent stream in line 24 is then cooled incooling device, in this instance a shell and tube heat exchanger 26,with the entrance and exit of a cooling fluid denoted by the unnumberedlines. The cooling of the compressed first vapor effluent stream in line24 through heat exchanger 26 serves to produce a second effluent streamin line 28 that is partially in the vapor state. The second effluentstream in line 28 is directed to flash drum 30 to effect the separationof the second effluent stream into a condensed liquid effluent stream inline 34 comprising C₅+ hydrocarbons and unreacted methanol and aresidual vapor effluent stream in line 32 comprising C₂ to C₄ olefins.The residual vapor effluent stream in line 32 is suitable for furtherprocessing to recover and purify the various olefins.

The condensed liquid effluent stream in line 34 is provided toliquid-liquid contacting device 36, in this instance a liquid-liquidextraction tower, at a point near the bottom of the extraction tower 36.A liquid water-containing stream in line 38 is also provided to a pointnear the top of extraction tower 36, and the contacting that occurstherein effects a separation of C₅+ hydrocarbons from the condensedliquid effluent stream in line 34 into an organic phase exiting in line40 from near the top of extraction tower 36 (the hydrocarbons in theorganic phase within extraction tower 36 are less dense than the waterwithin extraction tower 36, and hence tend to rise). Further, the waterfrom the liquid water-containing stream in line 38 that is withinextraction tower 36 stream will absorb the methanol, and substantialquantities of many other oxygenates that may be present from thecondensed liquid effluent stream in line 34, into an aqueous phase inline 42 from near the bottom of extraction tower 36 (the water in theaqueous phase within extraction tower 36 is more dense than thehydrocarbons within extraction tower 36, and thus tends to fall).

Directing attention to FIG. 2, there is illustrated therein a processfor converting an oxygenate to olefins according to a second example ofthe invention. An oxygenate feedstock, for example, methanol, isprovided in line 100 to oxygenate to olefin reactor 102 for conversionto a vapor product stream comprising C₂ to C₄ olefins, C₅+ hydrocarbons,C₂ to C₆ carbonyl compounds, unreacted methanol and water, which exitsthe oxygenate to olefin reactor 102 in line 104 at a reaction pressure.

The vapor product stream in line 104 is provided to a cooling device, inthis instance a quench tower 106. The cooling in quench tower 106 servesto condense from the vapor product stream in line 104 a liquidwater-rich bottoms stream in line 110 near the bottom of quench tower106, and also provide, from near the top of quench tower 106, a firstvapor effluent stream in line 108 at an initial pressure that is nogreater than the reaction pressure, and further that comprises no morethan 5 wt. % water.

The first vapor effluent stream in line 108 is provided to the suctionof a compressor 114 at a first suction pressure that is no greater thanthe initial pressure. The vapor product stream in line 108 is compressedin compressor 114 to produce a compressed first vapor effluent stream inline 116 that is at a second pressure greater than the first suctionpressure. The second vapor effluent stream in line 116 is then cooled incooling device, in this instance a shell and tube heat exchanger 118, toproduce a second effluent stream in line 120 that is at least partiallyin the vapor state.

The second effluent stream is communicated via line 120 to avapor-liquid contacting device, in this case absorber fractionationtower 122, at a point near the bottom of the absorber tower 122 to allowthe vapor portion of the second effluent stream to rise through thecontacting device. An alcohol wash is effected in absorber tower 122 byproviding a liquid alcohol-containing stream, in this case methanol, inline 124 to a point near the top of the absorber tower 122.Conveniently, the pressure in absorber tower 122 is greater than thefirst suction pressure but no greater than the second pressure.

The liquid methanol-containing stream in line 124 will flow down throughthe absorber tower 122, contacting the second effluent stream,preferentially absorbing C₂ to C₆ carbonyl compounds, and also absorbinga significant amount of C₅+ hydrocarbons, thus producing a wash liquidstream in line 128 from near the bottoms of absorber tower 122. Fromnear the top of absorber tower 122, a wash vapor stream is produced inline 126 that has a lower content of C₂ to C₆ carbonyl compounds thanthe first vapor effluent stream in line 108, suitable for furtherprocessing to recover and purify the various olefins. It is likely thatthe wash vapor stream in line 126 will further comprise some of themethanol contained in the liquid methanol-containing stream in line 124.

The wash liquid effluent stream in line 128 is provided to liquid-liquidcontacting device 130, in this instance a liquid-liquid extractiontower, at a point near the bottom of the extraction tower 130. A liquidwater-containing stream in line 136 is also provided to a point near thetop of extraction tower 130, and the contacting that occurs thereineffects a separation of C₅+ hydrocarbons from the wash liquid effluentstream in line 128 into an organic phase exiting in line 132 from nearthe top of extraction tower 130. Further, the water from the liquidwater-containing stream in line 136 that is within extraction tower 130stream will absorb the methanol (both the unreacted methanol from thevapor product stream in line 108 and the methanol from the liquidalcohol-containing stream in line 124), and substantial quantities ofmany other oxygenates that may be present from the condensed liquideffluent stream in line 128, into an aqueous phase in line 134 from nearthe bottom of extraction tower 130.

Now with regard to FIG. 3, there is illustrated therein a process forconverting an oxygenate to olefins according to a third example of theinvention. An oxygenate feedstock, for example methanol, is provided inline 202, along with a fraction rich in at least one oxygenate, againfor example containing methanol, in line 266, to oxygenate to olefinreactor 204. The methanol and any other oxygenates are converted to avapor product stream comprising C₂ to C₄ olefins, C₅+ hydrocarbons,unreacted methanol and water, which exits the oxygenate to olefinreactor 204 in line 206 at a reaction pressure.

The vapor product stream in line 206 is provided to a cooling device, inthis instance a quench tower 208. The cooling in quench tower 208 servesto condense from the vapor product stream in line 206 a liquidwater-rich bottoms stream in line 212 near bottom of quench tower 208,and also provide, from near the top of quench tower 208, a first vaporeffluent stream in line 210 at an initial pressure that is no greaterthan the reaction pressure, and further that comprises no more than 2wt. % water.

The first vapor effluent stream in line 210 is fed, via a flash drum214, and line 216, to the suction of a compressor 218 at a first suctionpressure that is no greater than the initial pressure. The flash drum214 also receives a common first condensed liquid effluent stream, firstflash liquid effluent stream and first wash flash liquid effluent streamthrough line 252, and exposes this common stream in line 252 to apressure of at least the first suction pressure and less than anintermediate pressure to produce a second flash vapor effluent streamand second wash flash vapor effluent stream, and a second flash liquideffluent stream and second wash flash liquid effluent stream. The secondflash vapor effluent stream and second wash flash vapor effluent streamexit the drum 214 through line 216, as a common stream with the firstvapor effluent stream in line 216, to the suction of compressor 218. Thesecond flash liquid effluent stream and second wash flash liquideffluent stream exit the drum 214 as a common stream through line 254,and carry with them at least part of the unreacted methanol and C₂ to C₆carbonyl compounds from the first vapor effluent stream in line 210.

The common stream in line 216 is compressed in compressor 218 to producea compressed first vapor effluent stream in line 220 that is at anintermediate pressure greater than the initial pressure. The compressedfirst vapor effluent stream in line 220 is then cooled in a coolingdevice, in this instance a shell and tube heat exchanger 222. Thecooling of the compressed first vapor effluent stream in line 220through heat exchanger 222 serves to produce a compressed and cooledfirst vapor effluent stream in line 224 (also termed herein a first“condensate”) that is partially in the vapor state. The first condensateis fed by line 224 to a another flash drum 226, where the firstcondensate is separated into a first residual effluent vapor stream inline 228 and the common first condensed liquid effluent stream, firstflash liquid effluent stream and first wash flash liquid effluent streamin line 252. The first residual effluent vapor stream in line 228 iscommunicated to the suction of another compressor 230 at an intermediatesuction pressure that is no greater than the intermediate pressure.

The second flash drum 226 also receives a second condensed liquideffluent stream through line 242 and a wash liquid stream through line250. In drum 226, the second condensed liquid effluent stream and thewash liquid stream are exposed to a pressure of at least theintermediate suction pressure and less than a third pressure to producea first flash vapor effluent stream and first wash flash vapor effluentstream, and a first flash liquid effluent stream and first wash flashliquid stream. The first flash vapor effluent stream and first washflash vapor effluent stream exit the drum 226 through line 228, as acommon stream with the first remaining vapor effluent vapor stream, tothe suction of compressor 230. Further, the first flash liquid effluentstream and first wash flash liquid streams exit the drum 226 throughline 252, as a common stream with the first condensed liquid effluentstream and are returned to the first flash drum 214.

The common stream in line 228 is compressed in compressor 230 to producea compressed first residual vapor effluent stream in line 232 that is ata second pressure greater than the intermediate pressure. The compressedfirst residual vapor effluent stream in line 232 is then cooled incooling device, in this example another shell and tube heat exchanger234, to produce a second effluent stream in line 236 that is partiallyin the vapor state. The second effluent stream in line 236 is fed to yetanother flash drum 238, to form the second condensed liquid effluentstream in line 242 and a second residual vapor effluent stream in line240 from near the top of flash drum 238.

The second residual vapor effluent stream is communicated via line 240to a vapor-liquid contacting device, in this case absorber fractionationtower 244, at a point near the bottom of the absorber tower 244. Analcohol wash is effected at the third pressure, greater than theintermediate suction pressure but not greater than the second pressure,in absorber tower 244 by providing a liquid alcohol-containing stream,in this case containing methanol, in line 246 at a point near the top ofthe absorber tower 244. The liquid methanol-containing stream in line246 flows down through the absorber tower 244, contacting the secondresidual vapor effluent stream, preferentially absorbing C₂ to C₆carbonyl compounds, and also absorbing C₅+ hydrocarbons, and some C₂ toC₄ olefins, thus producing the wash liquid stream in line 250 from nearthe bottoms of absorber tower 244. From near the top of absorber tower244, a wash vapor stream is produced in line 248 that has a lowercontent of C₂ to C₆ carbonyl compounds and C₅+ hydrocarbons than thefirst vapor effluent stream in line 210, suitable for further processingto recover and purify the various olefins. It is likely that the washvapor stream in line 248 will further comprise some of the methanolcontained in the liquid alcohol-containing stream in line 246.

The common second flash liquid effluent stream and second wash flashliquid effluent stream in line 254 is provided to liquid-liquidcontacting device 256, in this instance a liquid-liquid extractiontower, at a point near the bottom of the extraction tower 256. A liquidwater-containing stream in line 258 is also provided to a point near thetop of extraction tower 256, and the contacting that occurs thereineffects a separation of C₅+ hydrocarbons from the common liquid effluentstream in line 254 into an organic phase exiting in line 260 from nearthe top of extraction tower 256. Further, the water from the liquidwater-containing stream in line 258 that is within extraction tower 256stream will absorb the methanol (both the unreacted methanol from thevapor product stream in line 210 and the methanol from the liquidalcohol-containing stream in line 246), and quantities of the C₂ to C₆carbonyls that may be present from the common liquid effluent stream inline 254, into an aqueous phase in line 262 from near the bottom ofextraction tower 256.

Both the liquid water-rich bottoms stream in line 212 and the aqueousphase in line 262 are fed to a water-oxygenate fractionation tower 264that separates them into the overhead product fraction rich in at leastone oxygenate in line 266 and a substantially pure water as a bottomsstream in line 268. The overhead product fraction rich in at least oneoxygenate in line 266 is recycled as feed to the oxygenate to olefinreactor 204. A portion of the substantially pure water stream in line268 is used as the liquid water-containing stream in line 258 inextraction tower 256, and the balance of the substantially pure waterstream is directed elsewhere in line 270.

In an optional embodiment, the wash vapor effluent stream is subjectedto a second washing step in which the wash vapor effluent stream iswashed with water in a second vapor-liquid contacting device, againtypically a countercurrent fractional distillation tower, to produce awater-washed vapor effluent stream and an water wash liquid bottomsstream. Conveniently, the water employed in the second washing step isthe substantially pure water bottoms stream obtained from thewater-oxygenate fractionation tower. Moreover, the water wash liquidbottoms stream from the second washing step is conveniently returned tothe water-oxygenate fractionation tower to allow recovery and recycle ofthe water to the second washing step.

In general, the temperature employed in the second washing step shouldbe no more than 120° F. (49° C.) so as to enhance the oxygenateadsorption capacity of the water and limit the amount of water vaporexiting the second vapor-liquid contacting device with the water-washedvapor effluent stream. Conveniently, the temperature of the secondwashing step is at least 70° F. (21° C.), for example at least 80° F.(27° C.), such as at least 90° F., and no more than 110° F. (43° C.),for example no more than 100° F. (38° C.). Conveniently, the secondwashing step is conducted at or near said third pressure.

Conveniently, said water-washed vapor effluent stream comprises lessthan 0.5 wt. %, such as less than 0.1 wt %, for example less than 500ppmwt, of C₂ to C₆ carbonyl compounds based on the total weight ofwater-washed vapor effluent stream. In addition, the water-washed vaporeffluent stream conveniently comprises less than 1.0 wt. %, such as lessthan 0.1 wt %, for example less than 500 ppmwt, of methanol based on thetotal weight of water-washed vapor effluent stream. The water-washedvapor effluent stream can then be processed to recover the C₂ to C₄olefins and higher hydrocarbons present in this stream.

In one embodiment of such a recovery process, at least part of thewater-washed vapor effluent stream is contacted with a basic component,such as caustic or an amine, to remove the bulk of the carbon dioxidetherefrom, whereafter the CO₂-depleted stream is dried, for example in amolecular sieve drier, so that the dried effluent stream has a dew pointno greater than −150° F. (−101° C.), such as no greater than −200° F.(−129° C.). At least part of the dried effluent stream is thenfractionated to produce a C₃ and C₃-containing overhead stream and a C₄+containing bottoms stream. The C₃ and C₃-containing overhead can then beprocessed in conventional manner to separate the ethylene and propyleneproduct fractions.

The invention will now be more particularly described with reference tothe following practical example of the process shown in FIG. 1.

EXAMPLE

A pilot plant trial of the process shown in FIG. 2 was conducted inwhich the second effluent stream was washed in the absorberfractionation tower 122 at a pressure of 150 psig (1135 kPa) and amethanol flow rate of 15 lb/hour. The composition of the second vaporeffluent stream in line 116 and the wash vapor stream in line 126 areshown below in Table 1.

TABLE 1 Second Effluent Wash Vapor Component Stream (wt %) Stream (wt %)% Change Dimethyl ether 3.7661 2.7718 −26.4015 Methyl ethyl ether 0.01010.0000 −100.0000 Methyl isopropyl ether 0.0007 0.0000 −100.0000Acetaldehyde 0.0417 0.0378 −9.5362 2-Methoxy butane 0.0002 0.0000−100.0000 Propanal 0.0111 0.0000 −100.0000 Acrolein 0.0001 0.0000−100.0000 Methacrolein 0.0036 0.0000 −100.0000 Unknown 0.0003 0.0000−100.0000 Butanal 0.0032 0.0000 −100.0000 Methyl acetate 0.0002 0.0000−100.0000 Methanol 2.7353 2.3179 −15.2629 Acetone 0.1601 0.0813 −49.2466Isovaleraldehyde 0.0003 0.0000 −100.0000 Dimethylacetal 0.0020 0.0000−100.0000 Pentanal 0.0005 0.0000 −100.0000 2-Butanone 0.0375 0.0000−100.0000 Ethanol 0.0008 0.0000 −100.0000 3-Methyl-3-buten-2-one 0.00140.0000 −100.0000 Unknown 0.0002 0.0000 −100.0000 Crotonaldehyde 0.00020.0000 −100.0000 3-Methyl-2-butanone 0.0042 0.0000 −100.0000 3-Pentanone0.0021 0.0000 −100.0000 2-Methyl butanol 0.0002 0.0000 −100.00002-Pentanone 0.0022 0.0000 −100.0000 3-Butenol 0.0003 0.0000 −100.00003-Methyl-2-pentanone 0.0003 0.0514 19009.5609 t-Butanol 0.0001 0.0000−100.0000 Methane 1.2653 1.2563 0.0000 Ethane 0.5437 0.5308 −2.3655Ethylene 30.6933 29.9435 −2.4430 Propane 0.9249 0.7663 −17.1554Cyclopropane 0.0031 0.0000 −100.0000 Propylene 35.4988 31.0685 −12.4804Isobutane 0.0849 0.0587 −30.8560 n-Butane 0.2579 0.1672 −35.1748 Methylcyclopropane 0.0039 0.0000 −100.0000 Trans-2-Butene 5.1322 3.6158−29.5467 1-Butene 3.3856 2.5235 −25.4634 Iso-Butene 0.7129 0.5469−23.2929 Cis-2-Butene 3.8081 2.6364 −30.7689 Isopentane 0.0043 0.0349706.3496 1,2-Butadiene 0.0561 0.0000 −100.0000 Pentane 0.0581 0.0000−100.0000 Methyl acetylene 0.0022 0.0000 −100.0000 1.3-Butadiene 0.44570.0280 −93.7131 C5+ 10.3408 4.0294 −61.0339 H2O/CO/CO2 0.0000 0.1403Undefined

It will be seen from Table 1 that the methanol wash removes many of theoxygenates in the second vapor effluent stream, except for part of thedimethyl ether, acetaldehyde, acetone and 3-methyl-pentanone. However,it will be seen that the methanol wash step also removes non-negligibleamounts of ethylene and propylene product, and substantial amounts ofC₅+ hydrocarbons, which are managed advantageously in the method of thepresent invention.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For this reason, then, reference shouldbe made solely to the appended claims for purposes of determining thetrue scope of the present invention.

1. A process for producing olefins comprising: (a) providing a vaporproduct stream from an oxygenate to olefin conversion reactioncomprising C₂ to C₄ olefins, C₅+ hydrocarbons, at least one oxygenateand water; (b) cooling the vapor product stream to remove watertherefrom and produce a first vapor effluent stream; (c) compressing andcooling the first vapor effluent stream to produce a condensed liquideffluent stream comprising C₅+ hydrocarbons and at least one oxygenate,and a residual vapor effluent stream comprising C₂ to C₄ olefins; and(d) contacting at least a portion of the condensed liquid effluent steamwith a liquid water-containing stream in a liquid-liquid contactingdevice to at least partly separate said condensed liquid effluentstream, or portion thereof, into an aqueous phase rich in said at leastone oxygenate and an organic phase rich in said C₅+ hydrocarbons.
 2. Theprocess of claim 1 wherein said at least one oxygenate includesmethanol.
 3. The process of claim 2 wherein said vapor product stream in(a) comprises from about 1 wt. % to about 10 wt. % methanol.
 4. Theprocess of claim 1 wherein the first vapor effluent stream produced in(b) has a pressure ranging from about 108 kPaa (1 psig) to about 1480kPaa (200 psig).
 5. The process of claim 1 wherein the first vaporeffluent stream produced in (b) has a pressure ranging from about 108kPaa (1 psig) to about 791 kPaa (100 psig).
 6. The process of claim 1wherein the first vapor effluent stream produced in (b) has a pressureranging from about 136 kPaa (5 psig) to about 377 kPaa (40 psig).
 7. Theprocess of claim 1 wherein the first vapor effluent stream produced in(b) has a temperature ranging from about 20° C. (68° F.) to about 54° C.(130° F.).
 8. The process of claim 1 wherein the first vapor effluentstream produced in (b) has a temperature ranging from about about 32° C.(90° F.) to about 43° C. (110° F.).
 9. The process of claim 1 whereinthe condensed liquid effluent stream and the residual vapor effluentstream produced in (c) have a pressure ranging from about 446 kPaa (50psig) to about 2514 kPaa (350 psig).
 10. The process of claim 1 whereinthe coudensed liquid effluent stream and the residual vapor effluentstream produced in (c) have a pressure ranging fran, about 791 kPaa (100psig) to about 2100 kPaa (290 psig).
 11. The process of claim 1 whereinthe condensed liquid effluent stream and the residual vapor effluentstream produced in (c) have a pressure ranging from about 1066 kPaa (140psig) to about 1342 kPaa (180 psig).
 12. The process of claim 1 whereinthe condensed liquid effluent stream produced in (c) comprises up toabout 20 wt. % aromatics.
 13. The process of claim 1 wherein thecondensed liquid effluent stream produced in (c) comprises up to about10 wt. % aromatics.
 14. The process of claim 1 wherein the condensedliquid effluent stream produced in (c) comprises up to about 1 wt. %aromatics.
 15. The process of claim 1 wherein the condensed liquideffluent stream produced in (c) comprises up to about 10 wt. % benzene.16. The process of claim 1 wherein the condensed liquid effluent streamproduced in (c) comprises up to about 5 wt. % benzene.
 17. The processof claim 1 wherein the condensed liquid effluent stream produced in (c)comprises up to about 0.5 wt. % benzene.
 18. The process of claim 1wherein the condensed liquid effluent stream produced in (c) comprisesat least about 1 wt. % of said at least one oxygenate.
 19. The processof claim 1 wherein the condensed liquid effluent stream produced in (a)comprises at least about 10 wt. % of said at least one oxygenate. 20.The process of claim 1 wherein the condensed liquid effluent streamproduced in (c) comprises at least about 20 wt. % of said at least oneoxygenate.
 21. The process of claim 1 wherein the vapor product streamin (a) further comprises C₂ to C₆ carbonyls, and the condensed liquideffluent stream produced in (c) comprises at least 0.10 wt. % C₂ to C₆carbonyls.
 22. The process of claim 1 wherein the vapor product steam in(a) further comprises C₂ to C₆ carbonyls, and the condensed liquideffluent stream produced in (c) comprises at least 5 wt. % C₂ to C₆carbonyls.
 23. The process of claim 1 wherein the vapor product streamin (a) further comprises C₂ to C₆ carbonyls, and the condensed liquideffluent stream produced in (c) comprises at least 10 wt. % C₂ to C₆carbonyls.
 24. The process of claim 1 wherein (c) comprises compressingthe first vapor affluent stream, cooling the compressed first vaporeffluent stream to form a condensate and providing the condensate to avessel to separate the condensed liquid effluent stream from theresidual vapor effluent stream.
 25. The process of claim 1 wherein (c)comprises compressing the first vapor effluent stream; cooling thecompressed first vapor effluent stream to produce a first condensedliquid effluent steam and a first residual vapor effluent stream;compressing the first residual vapor effluent stream and cooling thecompressed first residual vapor effluent stream to produce a secondcondensed liquid effluent stream and a second residual vapor effluentstream and, further wherein at least a portion of the condensed liquideffluent stream in (d) is selected from the group consisting of thefirst condensed liquid effluent stream, the second condensed liquideffluent stream and mixtures thereof.
 26. The process of claim 1 whereinthe liquid water-containing stream in (d) comprises at least 90 wt. %water.
 27. The process of claim 1 wherein the liquid water-containingstream in (d) comprises at least 95 wt. % water.
 28. The process ofclaim 1 wherein said organic phase in (d) comprises up to about 95 wt. %C₅+ hydrocarbons.
 29. The process of claim 1 wherein said organic phasein (d) comprises up to about 75 wt. % C₅+ hydrocarbons.
 30. The processof claim 1 wherein said organic phase in (d) comprises up to about 40wt. % C₂ to C₆ carbonyls.
 31. The process of claim 1 wherein saidorganic phase in (d) comprises up to about 25 wt. % C₂ to C₆ carbonyls.32. The process of claim 1 wherein said contacting (d) is conductedwithin said liquid-liquid contacting device at a pressure of from about170 kPaa (10 psig) to about 2514 kPaa (350 psig), and a temperature offrom about 1° C. (34° F.) to about 54° C. (130° F.).
 33. The process ofclaim 1 wherein said contacting (d) is conducted within saidliquid-liquid contacting device at a pressure of from about 446 kPaa (50psig) to about 1480 kPaa (200 psig), and a temperature of from about 21°C. (70° F.) to about 43° C. (110° F.).
 34. The process of claim 1wherein the contacting (d) comprises feeding the liquid water-containingstream to the liquid-liquid contacting device at a first rate andfeeding the condensed liquid effluent stream to the liquid-liquidcontacting device at a second rate, wherein the weight ratio of thesecond rate to the first rate ranges from about 0.1 to about
 10. 35. Theprocess of claim 34 wherein the weight ratio of the second rate to thefirst rate ranges from about 0.2 to about
 2. 36. The process of claim 34wherein the weight ratio of the second rate to the first rate rangesfrom about 0.3 to about 1.4.
 37. The process of claim 34 wherein theweight ratio of the second rate to the first rate ranges from about 0.6to about 1.2.
 38. The process of claim 34 wherein said at least oneoxygenated hydrocarbon includes methanol and the weight ratio ofmethanol in the second rate to the first rate ranges from about 0.1 toabout
 1. 39. The process of claim 38 wherein the weight ratio ofmethanol in the second rate to the first rate ranges from about 0.2 toabout 0.7.
 40. The process of claim 38 wherein the weight ratio ofmethanol in the second rate to the first rate ranges from about 0.3 toabout 0.6.
 41. The process of claim 1 further comprising fractionatingthe aqueous phase into a water-rich fraction and a fraction rich in saidat least one oxygenate.
 42. The process of claim 41 wherein at least aportion of said liquid water-containing stream in (d) is at least aportion of said water-rich fraction.
 43. The process of claim 41 whereinat least part of said fraction rich in said at least one oxygenate isrecycled to said oxygenate to olefin conversion reaction.
 44. Theprocess of claim 1 further comprising exposing said condensed liquideffluent stream produced in (c) to one or more reductions in pressure toform a flash liquid effluent stream, wherein said flash liquid effluentstream is provided as the portion of the condensed liquid effluentstream for contacting (d).
 45. The process of claim 44 wherein the flashliquid effluent stream comprises up to about 20 wt. % aromatics.
 46. Aprocess for producing olefins comprising: (a) providing a vapor productstream from an oxygenate to olefin reaction comprising C₂ to C₄ olefins,C₅+ hydrocarbons, at least one oxygenate and water; (b) cooling thevapor product stream to remove water therefrom and produce a first vaporeffluent stream; (c) compressing and cooling the first vapor effluentstream to produce a second effluent stream that is at least partially inthe vapor state; (d) washing at least part of the second effluent streamwith a liquid alcohol-containing stream to remove at least a portion ofat least one oxygenate from the second effluent stream in a wash liquideffluent stream, and produce a wash vapor effluent stream comprising C₂to C₄ olefins, the wash liquid effluent stream further comprising C₅+hydrocarbons and alcohol contained in the liquid alcohol-containingstream; and (e) contacting at least a portion of the wash liquideffluent steam with a liquid water-containing stream in a liquid-liquidcontacting device to at least partially separate said wash liquideffluent stream, or portion thereof, into an aqueous phase rich in saidat least one oxygenate and alcohol from the liquid alcohol-containingstream, and an organic phase rich in said C₅+ hydrocarbons.
 47. Theprocess of claim 46 wherein said liquid alcohol-containing streamcomprises at least one alcohol from the group consisting of methanol andethanol.
 48. The process of claim 46 wherein said liquidalcohol-containing stream comprises methanol.
 49. The process of claim46 wherein the wash liquid effluent stream produced in (d) comprises upto about 20 wt. % aromatics.
 50. The process of claim 46 wherein thewash liquid effluent stream produced in (d) comprises up to about 10 wt.% aromatics.
 51. The process of claim 46 wherein the wash liquideffluent stream produced in (d) comprises up to about 1 wt. % aromatics.52. The process of claim 46 wherein the wash liquid effluent streamproduced in (d) comprises at least about 1 wt. % of said at least oneoxygenate.
 53. The process of claim 46 wherein the wash liquid effluentstream produced in (d) comprises at least about 10 wt. % of said atleast one oxygenate.
 54. The process of claim 46 wherein the wash liquideffluent stream produced in (d) comprises at least about 20 wt. % ofsaid at least one oxygenate.
 55. The process of claim 46 wherein thewash liquid effluent stream produced in (d) comprises at least about 10wt. % alcohol contained in the liquid alcohol-containing stream.
 56. Theprocess of claim 46 wherein the wash liquid effluent stream produced in(d) comprises at least about 20 wt. % alcohol contained in the liquidalcohol-containing stream.
 57. The process of claim 46 wherein theliquid water-containing stream in (e) comprises at least 90 wt. % water.58. The process of claim 46 wherein the liquid water-containing streamin (e) comprises at least 95 wt. % water.
 59. The process of claim 46wherein said organic phase in (e) comprises up to about 95 wt. % C₅+hydrocarbons.
 60. The process of claim 46 wherein said organic phase in(e) comprises up to about 75 wt. % C₅+ hydrocarbons.
 61. The process ofclaim 46 wherein said organic phase in (e) comprises up to about 40 wt.% C₂ to C₆ carbonyls.
 62. The process of claim 46 wherein said organicphase in (e) comprises up to about 25 wt. % C₂ to C₆ carbonyls.
 63. Theprocess of claim 46 wherein said contacting (e) is conducted at apressure of from about 170 kPaa (10 psig) to about 2514 kPaa (350 psig),and a temperature of from about 1° C. (34° F.) to about 54° C. (130°F.).
 64. The process of claim 46 wherein said contacting (e) isconducted within said liquid-liquid contacting device at a pressure offrom about 446 kPaa (50 psig) to about 1480 kPaa (200 psig), and atemperature of from about 21° C. (70° F.) to about 43° C. (110° F.). 65.The process of claim 46 further comprising exposing said wash liquideffluent stream produced in (d) to one or more reductions in pressure toform a wash flash liquid effluent stream, wherein said wash flash liquideffluent stream is provided as the portion of the wash liquid effluentstream for contacting (e).
 66. The process of claim 65 wherein the washflash liquid effluent stream comprises up to about 20 wt. % aromatics.67. The process of claim 65 wherein the wash flash liquid effluentstream comprises at least about 30 wt. % alcohol contained in the liquidalcohol-containing stream.
 68. The process of claim 46 wherein (c)comprises compressing the first vapor effluent stream; cooling thecompressed first vapor effluent stream to produce a first condensedliquid effluent stream and a first residual vapor effluent stream;compressing the first residual vapor effluent stream; and cooling thecompressed first residual vapor effluent stream to produce a secondresidual vapor effluent stream that is at least partially in the vaporstate, said second residual vapor effluent stream being provided forsaid washing (d).
 69. The process of claim 46 further comprisingfractionating the aqueous phase into a water-rich fraction and afraction rich in said at least one oxygenate.
 70. The process of claim46 wherein at least a portion of said liquid water-containing stream in(e) is at least a portion of said water-rich fraction.
 71. A process forproducing olefins comprising: (a) providing a vapor product stream froman oxygenate to olefin reaction comprising C₂ to C₄ olefins, C₅+hydrocarbons, at least one oxygenate and water; (b) cooling the vaporproduct stream to remove water therefrom and produce a first vaporeffluent stream; (c) compressing and cooling the first vapor effluentstream to produce a condensed liquid effluent stream comprising C₅+hydrocarbons and at least one oxygenate, and a residual vapor effluentsteam comprising C₂ to C₄ olefins, and; (d) washing at least part of theresidual vapor effluent stream with a liquid alcohol-containing streamto produce a wash vapor effluent stream comprising C₂ to C₄ olefins, anda wash liquid effluent stream comprising said at least one oxygenatedhydrocarbon and said C₅+ hydrocarbons; and (e) contacting at least aportion of the condensed liquid effluent stream produced in (c) and atleast a portion of the wash liquid effluent stream produced in (d) witha liquid water-containing stream in a liquid-liquid contacting device toat least partially separate said condensed liquid effluent streamproduced in (c) and the wash liquid effluent stream produced in (d), orportions thereof; into an aqueous phase rich in said at least oneoxygenate and alcohol contained in the liquid alcohol containing stream,and an organic phase rich in said C₅+ hydrocarbons.
 72. The process ofclaim 71 wherein said liquid alcohol-containing stream comprisesmethanol and/or ethanol.
 73. The process of claim 71 wherein said liquidalcohol-containing stream comprises methanol.
 74. The process of claim71 wherein the wash liquid effluent stream produced in (d) comprises upto about 20 wt. % aromatics.
 75. The process of claim 71 wherein thewash liquid effluent stream produced in (d) comprises up to about 10 wt.% aromatics.
 76. The process of claim 71 wherein the wash liquideffluent stream produced in (d) comprises up to about 1 wt. % aromatics.77. The process of claim 71 wherein the wash liquid effluent streamproduced in (d) comprises at least about 1 wt. % of said at least oneoxygenate.
 78. The process of claim 71 wherein the wash liquid effluentstream produced in (d) comprises at least about 10 wt. % of said atleast one oxygenate.
 79. The process of claim 71 wherein the wash liquideffluent stream produced in (d) comprises at least about 20 wt. % ofsaid at least one oxygenate.
 80. The process of claim 71 wherein thewash liquid effluent stream produced in (d) comprises at least about 10wt. % alcohol contained in the liquid alcohol-containing stream.
 81. Theprocess of claim 71 wherein the wash liquid effluent stream produced in(d) comprises at least about 20 wt. % alcohol contained in the liquidalcohol-containing stream.
 82. The process of claim 71 furthercomprising exposing said wash liquid effluent stream produced in (d) toone or more reductions in pressure to form a wash flash liquid effluentstream, wherein said wash flash liquid effluent stream is provided asthe portion of the wash liquid effluent stream for contacting (e). 83.The process of claim 82 wherein the wash flash liquid effluent streamcomprises up to about 20 wt. % aromatics.
 84. The process of claim 82wherein the wash flash liquid effluent stream comprises at least about20 wt. % alcohol contained in the liquid alcohol-containing stream. 85.The process of claim 82 wherein the wash flash liquid effluent streamcomprises at least about 30 wt. % alcohol contained in the liquidalcohol-containing stream.
 86. The process of claim 71 wherein theliquid water-containing stream in (e) comprises at least 90 wt. % water.87. The process of claim 71 wherein the liquid water-containing streamin (e) comprises at least 95 wt. % water.
 88. The process of claim 71wherein said organic phase in (e) comprises up to about 95 wt. % C₅+hydrocarbons.
 89. The process of claim 71 wherein said organic phase in(e) comprises up to about 75 wt. % C₅+ hydrocarbons.
 90. The process ofclaim 71 wherein said organic phase in (e) comprises up to about 40 wt.% C₂ to C₆ carbonyls.
 91. The process of claim 71 wherein said organicphase in (e) comprises up to about 25 wt. % C₂ to C₆ carbonyls.
 92. Theprocess of claim 71 wherein said contacting (e) is conducted at apressure of from about 170 kPaa (10 psig) to about 2514 kPaa (350 psig),and a temperature of from about 1° C. (34° F.) to about 54° C. (130°F.).
 93. The process of claim 71 wherein said contacting (e) isconducted within said liquid-liquid contacting device at a pressure offrom about 446 kPaa (50 psig) to about 1480 kPaa (200 psig), and atemperature of from about 21° C. (70° F.) to about 43° C. (110° F.). 94.The process of claim 71 further comprising fractionating the aqueousphase into a water-rich fraction and a fraction rich in said at leastone oxygenate.
 95. The process of claim 94 wherein at least a portion ofsaid liquid water-containing stream in (e) is at least a portion of saidwater-rich fraction.
 96. The process of claim 71 wherein said condensedliquid effluent stream and said wash liquid effluent stream, or portionsthereof, are combined, and said combined stream, or portion thereof, isprovided for contacting (e).
 97. The process of claim 71 wherein saidcondensed liquid effluent stream and said wash liquid effluent stream,or portions thereof, are combined, and said combined stream, or portionthereof, is exposed to one or more reductions in pressure to form aflash liquid effluent stream, wherein said flash liquid effluent streamis provided as the portion of the wash liquid effluent stream forcontacting (e).
 98. The process of claim 71 wherein (c) comprisescompressing the first vapor effluent stream; cooling the compressedfirst vapor effluent stream to produce a first condensed liquid effluentsteam and a first residual vapor effluent stream; compressing the firstresidual vapor effluent stream; and cooling the compressed firstresidual vapor effluent stream to produce a second effluent stream thatis at least partially in the vapor state, at least part of said secondeffluent stream being provided for said washing (d).
 99. The process ofclaim 98 wherein said second effluent stream is segregated into a secondcondensed liquid effluent stream and a second residual vapor effluentstream, said second residual vapor effluent stream being provided forsaid washing (d).
 100. The process of claim 99 wherein said firstcondensed liquid effluent stream, said second condensed liquid effluentstream or said wash liquid effluent steam, or portions thereof, isexposed to one or more reductions in pressure to form a flash liquideffluent stream, wherein said flash liquid effluent stream is providedas the portion of the condensed liquid effluent stream and wash liquideffluent stream for contacting (e).
 101. The process of claim 99 whereinsaid second condensed liquid effluent stream and said wash liquideffluent stream, or portions thereof, are exposed to a reduction inpressure along with the compressed and cooled first vapor effluentstream to produce a first residual vapor effluent stream and a commonfirst condensed liquid effluent stream and first flash liquid effluentstream, said common first condensed liquid effluent stream and firstflash liquid effluent stream being exposed to a further reduction inpressure to produce a second flash liquid effluent stream, and saidsecond flash liquid effluent stream being provided as the portion of thecondensed liquid effluent stream and wash liquid effluent stream forcontacting (e).